Correct network uuid field for os-network extension 

"nova net-list" does not return network uuid even when the uuid is
available, and instead returns only the id. This is because the
"network_dict" function in the extension improperly uses "in" to check
for a Network model object. This also reduces compatibility in the API.

Fixes bug: 1162409

Change-Id: I30d4c8bfa37d89123f35ee8cc7c67f0e819262a7
Signed-off-by: Zhi Yan Liu <zhiyanl@cn.ibm.com>
Merge "Correct network uuid field for os-network extension "