Additional logging and better error reporting on assert fail

Signed-off-by: Prasanna Santhanam <tsp@apache.org>
(cherry picked from commit 05bb315636eba87722ce3f49fe61bdd6bc4dcc32)
CLOUDSTACK-4262: Wait twice network.gc for vpcvr shutdown

Wait a little bit longer for the VpcVr to shutdown on network shutdown.

Signed-off-by: Prasanna Santhanam <tsp@apache.org>
(cherry picked from commit 4ed5033a59c7aa5fe95f865c5fcbdba21c03616e)
CLOUDSTACK-4258: Additional debug to the assertion

Signed-off-by: Prasanna Santhanam <tsp@apache.org>