Fix tracking of SG's provisioned by Heat

Reasons:
 - Trove doesn't track security group that was created as
   a part of stack.
 - Trove should create two records for security group tracking:
   - security group;
   - security group association with an actual instance;

Changes:
 - Adding security groups registration right after stack creation.

Change-Id: I1f55c27ecbd5ad76c869eae7197b8c24720fc1e6
Closes-Bug: #1276228
Merge "Fix tracking of SG's provisioned by Heat"