update run_system_tests.sh to record/use exit code
update run_system_tests.sh to record/use exit code

Record an exit code if the previous command fails.
Use that exit code to exit at the very end so collection can work.

Signed-off-by: Matthew Thode <1428de2d70d1c53cd978750576cb0eaf318833d1@mthode.org>

jacobwagner/rpc-openstack,cloudnull/rpc-openstack,BjoernT/rpc-openstack,jacobwagner/rpc-openstack,rcbops/rpc-openstack,rcbops/rpc-openstack,BjoernT/rpc-openstack,hughsaunders/rpc-openstack,cloudnull/rpc-openstack,hughsaunders/rpc-openstack