make QuantumV2 support requested nic ordering

fixes bug 1064524

The QuantumV2 did not honor nic ordering, so nics were attached in
Quantum's db natural order.  This patch sorts the networks honor requested nic
ordering when Nova calls the V2Quantum API.  Unit tests have been updated to
confirm ordering is honored.

Change-Id: I44a6a4736c78e86e83b6e682e63f93a5b47652da