Set InnoDB engine for all existing tables

Added the method in heal script that checks if mysql_engine
parameter is needed to be changed and if it is neseccary do this.
Also this change adds migation that set 'mysql_engine' to InnoDB
for all tables that were added into the database after healing.

Closes-bug: #1346966

Change-Id: Ia4d9038b99b2559d37272a17f5819a9dedd53f72
Fix migration set_length_of_description_field_metering

If PostgreSQL version is less than 9.1.13 migration
set_length_of_description_field_metering fails as there is no
special 'create if not exist' expression. This change add special
function for this case.

Closes-bug: #1348138

Change-Id: Ibe4f370fe400072abd281bd2313261790335eae2
Refresh rpc_backend values in unit tests to those from oslo.messaging

Though old values are supported via compatibility transport aliases [1],
it's better to stick to those values that are officially supported by
oslo.messaging.

[1]: neutron/common/rpc.py:TRANSPORT_ALIASES

blueprint oslo-messaging

Change-Id: I7bc03e323151cfdda2cb2bc4cd6f5aea9b87a746
Merge "Set InnoDB engine for all existing tables"
Merge "Fix migration set_length_of_description_field_metering"
Merge "Refresh rpc_backend values in unit tests to those from oslo.messaging"