Enhance fabric object yang model
Enhance fabric object yang model

 - add port attribute in fabric
 - add parent fabric reference
 - add capacity attribute

Change-Id: I6db4e6b956eb93bbf3b2d9a665791365e12a7931
Signed-off-by: xingjun <0d4e96fb144e023c98eb6de2c8ba5af17d0549a5@huawei.com>

opendaylight/faas