RE-613 Respect artifact location environment vars
RE-613 Respect artifact location environment vars

RE provide environment variables which hold the path to the
correct place to store artifacts and test results:
  * RE_HOOK_ARTIFACT_DIR
  * RE_HOOK_RESULT_DIR

These are now available in the IRR jobs so can be used here.

npawelek/rpc-maas,briancurtin/rpc-maas,cloudnull/rpc-maas,npawelek/rpc-maas,cloudnull/rpc-maas,cloudnull/rpc-maas,npawelek/rpc-maas,briancurtin/rpc-maas,cfarquhar/rpc-maas,cfarquhar/rpc-maas,briancurtin/rpc-maas,cfarquhar/rpc-maas