The router interface cannot be deleted since the MetaPlugin
cannot get the flavor information from the port which has
been deleted.
The solution is setting up the alias for each device based
on the flavor information, so the MetaPlugin still can get
the flavor information from the device itself even the
port has been deleted.
Also the router interface cannot be deleted since the
l3_port_check flag is not passed by MetaPlugin.
Fixes: bug #1085276
Change-Id: I670aa45c804e660ee4afb5359e0ab1347f369986
53ebb63410