Make nova-network support requested nic ordering

The nova-network did not honor nic ordering, so nics were attached in db
natural order. This patch sorts the networks honor requested nic
ordering when Nova calls the nova-network API.

Fixes bug: #1170725

Change-Id: I7dd04ac7bdda95c626cbb0fe35be0aadacb4bd2a
Signed-off-by: zhiyanl-cn <zhiyanl@cn.ibm.com>
Merge "Make nova-network support requested nic ordering"