Fix nic order not correct after reboot

Previously if an instance was rebooted or migrated the original nic order
would not be maintained. This patch retrieves the correct nic order from
info_cache so that the order is mantained.

Fixes bug 1187092

Change-Id: I3f5488cc14c692fde7d5bd3376389e2f2f5550ff
(cherry picked from commit bcd12a776e8cde8c4b64e7c1a21a7387ece55b31)
Merge "Fix nic order not correct after reboot" into stable/grizzly