Updated openstack/openstack
Project: openstack/python-keystoneclient  290a3be313189a428a838dfc1a9c405d44c1685e
null
Replace assertTrue with explicit assertIsInstance

assertIsInstance can provide useful message when test fails,
this patch replaces assertTrue(isinstance(x, y)) with
assertIsInstance(x, y).

Change-Id: I1a36b4f343c881b6690389753270d35599b758ab
Closes-Bug: #1268480