jenkins.sh: output all test logs when 'make check' failed

Assume that cat-testlogs.sh from osmo-ci is installed in $HOME/osmo-ci/scripts,
and call from jenkins.sh upon 'make check' failure.

Change-Id: I18a08e7ade1a53783d5a4171fe825f61b49457be
diff --git a/contrib/jenkins.sh b/contrib/jenkins.sh
index 5c69da6..e9f63e4 100755
--- a/contrib/jenkins.sh
+++ b/contrib/jenkins.sh
@@ -1,8 +1,10 @@
 #!/usr/bin/env bash
+export PATH="$PATH:$HOME/osmo-ci/scripts"
 
 set -ex
 
 autoreconf --install --force
 ./configure --enable-static
 $MAKE $PARALLEL_MAKE
-$MAKE distcheck
+$MAKE distcheck \
+  || cat-testlogs.sh