Change assertTrue(isinstance()) by optimal assert

Some of tests use different method of assertTrue(isinstance(A, B)) or
assertEqual(type(A), B). The correct way is to use assertIsInstance(A,
B) provided by testtools.

Change-Id: I8426ee1f6387602660f2d768883d18ab2f04c6f0
Closes-bug: #1268480
Enhancing tests to check project deletion in Active Directory

It includes a delete tree extension for fakeldap.

Change-Id: I91f732e2944f27d28074c77bcad853c729e9d659
Related-Bug: #1247032
Remove unused method _get_domain_conf

The _get_domain_conf method in keystone.identity.Manager is not used,
tested, or documented, so remove it.

Change-Id: I332b473806df7416f175573d1f43c3c64b0619c3
Fix indentation issue

The comment line was not indented properly.

Change-Id: I9c8987174af92082383a3cb99b5c73ead4e5da78
Merge "Remove unused method _get_domain_conf"
Merge "Fix indentation issue"
Merge "Change assertTrue(isinstance()) by optimal assert"
Merge "Enhancing tests to check project deletion in Active Directory"