Make admin consistent

There are variety like "admin" or "administrator" on api-guide,
so this patch makes these words consistent for the readability.

Partially implements blueprint complete-todo-in-api-concept-doc

Change-Id: Id0a9444e5d48f62d6d02114f8668761647c2dae0

api-guide/source/faults.rst

@@ -39,8 +39,8 @@ Instance Faults
 ---------------
 
 Nova often adds an instance fault DB entry for an exception that happens
-while processing an API request. This often includes more admin focused
-information, such as a stack trace.
+while processing an API request. This often includes more administrator
+focused information, such as a stack trace.
 However, there is currently no API to retrieve this information.
 
 Notifications

api-guide/source/general_info.rst

@@ -70,7 +70,7 @@ several key concepts:
    Quotas can be used to limit the number of servers a tenant creates, or the
    amount of disk space consumed, so that no one tenant can overwhelm the
    system and prevent normal operation for others. Changing quotas is an
-   admin-level action.
+   administrator-level action.
 
 -  **Rate Limiting**
 
@@ -83,8 +83,8 @@ several key concepts:
    zone" is used in other clouds, such as Amazon Web Services, to denote a
    physical separation of server locations that can be used to distribute cloud
    resources for fault tolerance in case one zone is unavailable for any
-   reason. Such a separation is possible in Nova if an admin carefully sets up
-   availability zones for that, but it is not the default.
+   reason. Such a separation is possible in Nova if an administrator carefully
+   sets up availability zones for that, but it is not the default.
 
 -  **User data**
    A user data file is a special key in the metadata service that holds a file
@@ -188,7 +188,8 @@ on compute hosts rather than servers.
    - **enable, disable, disable-log-reason**
 
      The service can be disabled to indicate the service didn't provided
-     service anymore. This is used by admin to stop service for maintenance.
+     service anymore. This is used by administrator to stop service for
+     maintenance.
      For example, when Administrator wants to maintain a specific compute node,
      Administrator can disable nova-compute service on that compute node. Then
      nova won't dispatch any new compute request to that compute node anymore.

api-guide/source/server_concepts.rst

@@ -217,8 +217,8 @@ Server actions
    be deleted will still be in the system. If this value is greater than 0,
    the deleted server will not be deleted immediately, instead it will be put
    into a queue until it's too old(deleted time greater than the value of
-   CONF.reclaim_instance_interval). Admin is able to use Restore action to
-   recover the server from the delete queue. If the deleted server stays
+   CONF.reclaim_instance_interval). Administrator is able to use Restore action
+   to recover the server from the delete queue. If the deleted server stays
    more than the CONF.reclaim_instance_interval, it will be deleted by compute
    service automatically.
 
@@ -236,7 +236,7 @@ Server actions
 
    Shelve offload is used to explicitly remove a shelved server that has been
    left on a host. This action can only be used on a shelved server and is
-   usually performed by an admin.
+   usually performed by an administrator.
 
    Unshelve is the reverse operation of Shelve. It builds and boots the server
    again, on a new scheduled host if it was offloaded, using the shelved image
@@ -245,7 +245,7 @@ Server actions
 -  **Lock**, **Unlock**
 
    Lock a server so no further actions are allowed to the server. This can
-   be done by either admin or the server's owner.
+   be done by either administrator or the server's owner.
 
    Unlock will unlock an server in locked state so additional
    operations can be performed on the server.
@@ -259,15 +259,15 @@ Server actions
    Unrescue is the reverse action of Rescue, the server spawned from the special
    root image will be deleted.
 
--  **Set admin password**
+-  **Set administrator password**
 
-   Set the root/admin password for the given server, it uses an
-   optional installed agent to inject the admin password.
+   Set the root/administrator password for the given server, it uses an
+   optional installed agent to inject the administrator password.
 
 -  **Migrate**, **Live migrate**
 
-   Migrate is usually utilized by admin, it will move a server to another
-   host; it utilize the 'resize' action but with same flavor, so during
+   Migrate is usually utilized by administrator, it will move a server to
+   another host; it utilize the 'resize' action but with same flavor, so during
    migration, the server will be power off and rebuilt on another host.
 
    Live migrate also moves an server from one host to another, but it won't