Fix multiple fixed-ips with quantum.

This patch fixes a bug in the quantum suppot where multiple requested
fixed-ips did not work.  Every network interface would be given the last
fixed IP that was specified.  The problem was just the lack of putting
the right fixed ip in a local variable.

Fix bug 1154093.

Change-Id: Ie7e034e19a38c8431540c81b023ff4800aa6ec50