Test: force remove the master containers if the jenkins fails to start

This will avoid leaving running container in the background whereas
the test has failed.

Change-Id: Ide8f940a6834a090693bcf22e98cd6f496ce2221
diff --git a/jenkins/test/common.sh b/jenkins/test/common.sh
index 41ae13c..932b405 100755
--- a/jenkins/test/common.sh
+++ b/jenkins/test/common.sh
@@ -98,6 +98,7 @@
   wait_for_server "${server}" "${port}" >&2 || {
     echo "Docker logs:" >&2
     ${DOCKER} logs "$jenkins"
+    ${DOCKER} rm -f "${jenkins}" >&2
     exit 1
   }
   local containers="$(run_containers "${jenkins}" | xargs)"