lockutils: fix testcase wrt Semaphore

Nothing returns anymore an eventlet semaphore, so stop trying to check
for that.

Change-Id: I272b754875259604565c9b658cf76a3378f71cc2
lockutils: split code handling internal/external lock

This makes the code much more readable and hackable.

Change-Id: I7f209c793eb7e2c5daaa068835d29a12a7e064a8
Utilizes assertIsNone and assertIsNotNone

Using assertEqual/assertNotEqual to test if an element
is or is not None is too python2.4.
Our unit testing framework supports assertIsNone and assertIsNotNone
which were created for these types of tests.

Change-Id: I29f915ae79bf4f8e9298c5de5d6087828fb0ca4f
Merge "Utilizes assertIsNone and assertIsNotNone"
Merge "lockutils: fix testcase wrt Semaphore"
Merge "lockutils: split code handling internal/external lock"