Fix HTTP response for PortInUse during boot

If an in use port is passed as a network parameter in the request, Nova API
should raise an HTTPConflict (409) error

Fixes bug #1160887

Change-Id: I60103610f9143f1c668927fe40d10a14b39b4c25
Merge "Fix HTTP response for PortInUse during boot"
Merge remote-tracking branch 'm_src_repo/citrix-fixes' into build-temp