Port update with no security groups

Port update with no security groups

(a) Cache was updated after added ACLs were processed during port update.
This was casuing problems when port was updated from no security groups to
valid security groups; required flows were not getting added in remote
group tables. This issue is fixed by updating cache before processing of
added ACLs.

(b) Port update to no security groups was leaving stale flows in remote
group tables sometimes. This was because of cache update happening in
different thread than the thread which was processing deleted ACLs. This
issue is fixed by passing copy of required unchanged cache to the thread
which is processin deleted ACLs.

(c) Remote group flow was getting deleted even though it was part of other
rules (of the same or different SG) of the port. Validation is introduced
to check this condition now before remote group flow is deleted.

Change-Id: I15022652ddb36ade060c3c26149c5d68594e1593
Signed-off-by: Shashidhar Raja <shashidharr@altencalsoftlabs.com>