jenkins: use osmo-clean-workspace.sh before and after build

See osmo-ci change I2409b2928b4d7ebbd6c005097d4ad7337307dd93 for rationale.

Depends: I2409b2928b4d7ebbd6c005097d4ad7337307dd93
Change-Id: I609f7c7c88b49f26e2e48e1f1cffed76d9e6fb5e
diff --git a/contrib/jenkins.sh b/contrib/jenkins.sh
index 80d6612..f31579e 100755
--- a/contrib/jenkins.sh
+++ b/contrib/jenkins.sh
@@ -1,7 +1,12 @@
 #!/bin/sh
 set -ex
+
+osmo-clean-workspace.sh
+
 autoreconf --install --force
 ./configure
 $MAKE $PARALLEL_MAKE
 $MAKE check \
   || cat-testlogs.sh
+
+osmo-clean-workspace.sh