tests: Remove unused fake method

The FakeServerMigration.get_server_migrations method was added in
change I15b4a5aca8d0dee59dd293e7b1c7272cdfbeea20 but has never been
used. Remove it.

Change-Id: I6089c5200737b9319a8e96f2a2fc18b7cdd6b2c6
Signed-off-by: Stephen Finucane <sfinucan@redhat.com>

Author: stephenfin

openstackclient/tests/unit/compute/v2/fakes.py

@@ -1631,22 +1631,3 @@ def create_server_migrations(attrs=None, methods=None, count=2):
                     attrs, methods))
 
         return migrations
-
-    @staticmethod
-    def get_server_migrations(migrations=None, count=2):
-        """Get an iterable MagicMock object with a list of faked migrations.
-
-        If server migrations list is provided, then initialize the Mock object
-        with the list. Otherwise create one.
-
-        :param List migrations:
-            A list of FakeResource objects faking server migrations
-        :param int count:
-            The number of server migrations to fake
-        :return:
-            An iterable Mock object with side_effect set to a list of faked
-            server migrations
-        """
-        if migrations is None:
-            migrations = FakeServerMigration.create_server_migrations(count)
-        return mock.Mock(side_effect=migrations)