Add ModelSMigrationSync classes

Add classes for testing correspondence between migration scripts
and metadata.
We need oslotest in test-requirements due to bug#1356425

Partial-Bug: #1365436
Change-Id: I0db68ea3557dd9d214ea50ff7c96de1a47a58d4b
Remove openstack.common.gettextutils module

Remove obsolete module from glance.

With the dependent change I84511ab1ee600e618985448dfbfbdc26cb130370,
Glance do not use obsolete modules from oslo-incubator anymore.

Closes bug: #1381870
Change-Id: I3c0441bcffffe671cf974dc7af14cbac66709d85
Signed-off-by: Zhi Yan Liu <zhiyanl@cn.ibm.com>
Merge "Remove openstack.common.gettextutils module"
Merge "Add ModelSMigrationSync classes"