Problem: if a user issue the cmd 'openstack floating ip create public'
and has already maxed his quota for FIP, OSC exits with a not so useful
message:
>jordan@jordan-XPS13-9333:~ $ openstack floating ip create public
>HttpException: Conflict
This patches catch the HttpException earlier and prints a more
verbose message:
> jordan@jordan-XPS13-9333:~ $ openstack floating ip create public
> Error while executing command: Quota exceeded for resources: ['floatingip']
Change-Id: I7c87524d871d230d92f007c32e06439b34c7194a