Fix the representation of REST

According to the wikipedia page, Representational
state transfer should be written as REST but in some
files it is written as ReST, so I changed it to
correct one

Change-Id: I1909b09fbe3e4ed99d817fdaf0006ef55367e74d
Closes-Bug: #1488816

README.rst

@@ -12,4 +12,4 @@ For more information, please refer to the following resources:
 * **Source:** http://git.openstack.org/cgit/openstack/magnum
 * **Blueprints:** https://blueprints.launchpad.net/magnum
 * **Bugs:** http://bugs.launchpad.net/magnum
-* **ReST Client:** http://git.openstack.org/cgit/openstack/python-magnumclient
+* **REST Client:** http://git.openstack.org/cgit/openstack/python-magnumclient

doc/source/index.rst

@@ -25,7 +25,7 @@ for deploying and managing containers as first class resources in OpenStack.
 * **Source:** http://git.openstack.org/cgit/openstack/magnum
 * **Blueprints:** https://blueprints.launchpad.net/magnum
 * **Bugs:** http://bugs.launchpad.net/magnum
-* **ReST Client:** http://git.openstack.org/cgit/openstack/python-magnumclient
+* **REST Client:** http://git.openstack.org/cgit/openstack/python-magnumclient
 
 Architecture
 ============
@@ -45,20 +45,20 @@ There are several different types of objects in the magnum system:
 * **Container:** A Docker container
 
 Two binaries work together to compose the magnum system.  The first binary
-(accessed by the python-magnumclient code) is the magnum-api ReST server.  The
-ReST server may run as one process or multiple processes.  When a ReST request
+(accessed by the python-magnumclient code) is the magnum-api REST server.  The
+REST server may run as one process or multiple processes.  When a REST request
 is sent to the client API, the request is sent via AMQP to the
-magnum-conductor process.  The ReST server is horizontally scalable.  At this
+magnum-conductor process.  The REST server is horizontally scalable.  At this
 time, the conductor is limited to one process, but we intend to add horizontal
 scalability to the conductor as well.
 
 The magnum-conductor process runs on a controller machine and connects to a
-Kubernetes or Docker ReST API endpoint.  The Kubernetes and Docker ReST API
+Kubernetes or Docker REST API endpoint.  The Kubernetes and Docker REST API
 endpoints are managed by the bay object.
 
 When service or pod objects are created, Kubernetes may be directly contacted
-via the Kubernetes ReST API.  When container objects are acted upon, the
-Docker ReST API may be directly contacted.
+via the Kubernetes REST API.  When container objects are acted upon, the
+Docker REST API may be directly contacted.
 
 Features
 ========

specs/containers-service.rst

@@ -83,7 +83,7 @@ Use cases
    multiple hosting environments). End-users want a single service that could
    help them build the container network, and dynamically modify the network
    topology by adding or removing containers to or from the network.
-9. Permit secure use of native ReST APIs. Provide two models of operation with
+9. Permit secure use of native REST APIs. Provide two models of operation with
    Magnum.  The first model allows Magnum to manage the lifecycle of Pods,
    ReplicationControllers, and Services.  The second model allows end-users to
    manage the lifecycle of Pods, ReplicationControllers, and Services by