contrib/jenkins.sh: run "make maintainer-clean"

Related: OS#3047
Change-Id: I619499ce68c8e0ddef597021329d9bfd4d2f1a77
diff --git a/contrib/jenkins.sh b/contrib/jenkins.sh
index 1a14278..249df64 100755
--- a/contrib/jenkins.sh
+++ b/contrib/jenkins.sh
@@ -39,5 +39,6 @@
 $MAKE $PARALLEL_MAKE
 $MAKE distcheck \
   || cat-testlogs.sh
+$MAKE maintainer-clean
 
 osmo-clean-workspace.sh