Fixes identified during parallel sanity run

Extend validation before project delete
pick change from master for default SG validation in project test
Dont use medium flavor for most VMs, use a new flavor contrail_flavor_2cpu
Some minor bug fixes

Change-Id: I4dcf3d2f263ae925dbb8b283e79e28d35214c4ce
Merge pull request #40 from vedujoshi/test_parallelism

Fixes identified during parallel sanity run