Compatible with the no mapping in network.yml

1)resolve the error  ' AttributeError: 'NetworkConfig' object has
no attribute 'ext_mapping'' with the no mapping in network.yml.

2)resolve the creating external subnet failure if the external
netwok exists.

Change-Id: I578365d91b8b61f9f88a5d4ff2c9db9ecc512edc
Signed-off-by: zhongjun <zhong.jun@zte.com.cn>

0 files changed, 0 insertions, 0 deletions