Deprecate the old API microversion fixture

We have moved the API microversion fixture to
tempest.lib.common.api_microversion_fixture location.

This commit deprecates the old fixture so that we can
remove them in Z cycle.

Change-Id: If38aa21a4cd99d2a5fe4a5c3b41214cd54f97f8d
diff --git a/tempest/api/compute/api_microversion_fixture.py b/tempest/api/compute/api_microversion_fixture.py
index 695af52..1f55a65 100644
--- a/tempest/api/compute/api_microversion_fixture.py
+++ b/tempest/api/compute/api_microversion_fixture.py
@@ -13,14 +13,23 @@
 # under the License.
 
 import fixtures
+from oslo_log import log as logging
 
 from tempest.lib.services.compute import base_compute_client
 
+LOG = logging.getLogger(__name__)
+
 
 class APIMicroversionFixture(fixtures.Fixture):
 
     def __init__(self, compute_microversion):
         self.compute_microversion = compute_microversion
+        new_fixture = (
+            'tempest.lib.common.api_microversion_fixture.'
+            'APIMicroversionFixture')
+        LOG.warning("%s class is deprecated and moved to %s. It"
+                    " will be removed in Z cycle.",
+                    self.__class__.__name__, new_fixture)
 
     def _setUp(self):
         super(APIMicroversionFixture, self)._setUp()