ci: Make sure .jenkins script stops when individual scripts returned error

Change-Id: Ie8bacfb957f6b54f04d9d09e64e79a594cdfc96d
Refs: #2089
diff --git a/.jenkins.d/20-tests.sh b/.jenkins.d/20-tests.sh
index ab404ae..c9b1e94 100755
--- a/.jenkins.d/20-tests.sh
+++ b/.jenkins.d/20-tests.sh
@@ -1,5 +1,6 @@
 #!/usr/bin/env bash
 set -x
+set -e
 
 # Prepare environment
 rm -Rf ~/.ndnx ~/.ndn