Fix issue when disassociating resources from firewall group

When disassociating ports from firewall group to cleanup resources,
an error is occurred without waiting for the firewall status to complete.

Change-Id: I12a91e75584d5e967d81abab32acf4258995a396
Closes-Bug: #1870296
Signed-off-by: ZijianGuo <guozijn@gmail.com>
2 files changed