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

Related: OS#3047
Change-Id: Ifb581662b05d938acc04636c2a408e43bbe10bf0
diff --git a/contrib/jenkins.sh b/contrib/jenkins.sh
index cf53c3a..2e9035d 100755
--- a/contrib/jenkins.sh
+++ b/contrib/jenkins.sh
@@ -38,5 +38,6 @@
 $MAKE $PARALLEL_MAKE
 LD_LIBRARY_PATH="$inst/lib" $MAKE check || cat-testlogs.sh
 LD_LIBRARY_PATH="$inst/lib" DISTCHECK_CONFIGURE_FLAGS="" $MAKE distcheck || cat-testlogs.sh
+$MAKE maintainer-clean
 
 osmo-clean-workspace.sh