Fix quantum security group driver to accept none for from/to_port

The quantum security group driver did not accept none values for
from_port/to_port which the nova security group api supports. This
patch allows None values to be passed in for those params and adds a unit test.

In addition the from/to_port responses would be different if using quantum
instead of nova. This patch fixes that and adds unit tests.

Fixes bug 1176027

Change-Id: Id57e253c9dd1787ee25fc5cbb562743692d7abe4
(cherry picked from commit 78e2e2128992527407f99743340692ef3be75210)
Merge "Fix quantum security group driver to accept none for from/to_port" into stable/grizzly