remove neutron.db.api references

While the initial version of this patch removed neutron.db.api, a
different duplicate patch [1] landed first.

This patch cleans up the remining references to neutron.db.api
including those in the docs and comments.

[1] https://review.openstack.org/#/c/635978/

Change-Id: I5f911f4c6a1fc582a9c1006ec5e2880853ff2909

doc/source/contributor/internals/quality_of_service.rst

@@ -218,7 +218,7 @@ instantiated (and to suggest just that, the base rule class is marked as ABC).
 
 QoS objects rely on some primitive database API functions that are added in:
 
-* neutron.db.api: those can be reused to fetch other models that do not have
+* neutron_lib.db.api: those can be reused to fetch other models that do not have
   corresponding versioned objects yet, if needed.
 * neutron.db.qos.api: contains database functions that are specific to QoS
   models.

doc/source/contributor/internals/quota.rst

@@ -222,7 +222,7 @@ In order to ensure correct operations, a row-level lock is acquired in
 the transaction which creates the reservation. The lock is acquired when
 reading usage data. In case of write-set certification failures,
 which can occur in active/active clusters such as MySQL galera, the decorator
-neutron.db.api.retry_db_errors will retry the transaction if a DBDeadLock
+neutron_lib.db.api.retry_db_errors will retry the transaction if a DBDeadLock
 exception is raised.
 While non-locking approaches are possible, it has been found out that, since
 a non-locking algorithms increases the chances of collision, the cost of

doc/source/contributor/internals/retries.rst

@@ -24,7 +24,7 @@
 Retrying Operations
 ===================
 
-Inside of the neutron.db.api module there is a decorator called
+Inside of the neutron_lib.db.api module there is a decorator called
 'retry_if_session_inactive'. This should be used to protect any
 functions that perform DB operations. This decorator will capture
 any deadlock errors, RetryRequests, connection errors, and unique

neutron/db/db_base_plugin_v2.py

@@ -434,7 +434,7 @@ class NeutronDbPluginV2(db_base_plugin_common.DbBasePluginCommon,
                         action='access_as_shared', target_tenant='*')
 
                 # TODO(ihrachys) Below can be removed when we make sqlalchemy
-                # event listeners in neutron/db/api.py to refresh expired
+                # event listeners in neutron_lib/db/api.py to refresh expired
                 # attributes.
                 #
                 # First trigger expiration of rbac_entries.

neutron/hacking/checks.py

@@ -246,7 +246,7 @@ def check_python3_no_filter(logical_line):
 # TODO(boden): rehome this check to neutron-lib
 @flake8ext
 def check_no_sqlalchemy_event_import(logical_line, filename, noqa):
-    """N346 - Use neutron.db.api.sqla_listen instead of sqlalchemy event."""
+    """N346 - Use neutron_lib.db.api.sqla_listen rather than sqlalchemy."""
     if noqa:
         return
     is_import = (logical_line.startswith('import') or