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

Change-Id: Ie8bacfb957f6b54f04d9d09e64e79a594cdfc96d
Refs: #2089

.jenkins

@@ -1,4 +1,5 @@
 #!/usr/bin/env bash
+set -e
 
 DIR=$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd )
 

.jenkins.d/10-build.sh

@@ -1,5 +1,6 @@
 #!/usr/bin/env bash
 set -x
+set -e
 
 # Cleanup
 sudo ./waf distclean -j1 --color=yes

.jenkins.d/20-tests.sh

@@ -1,5 +1,6 @@
 #!/usr/bin/env bash
 set -x
+set -e
 
 # Prepare environment
 rm -Rf ~/.ndnx ~/.ndn

.jenkins.d/30-coverage.sh

@@ -1,5 +1,6 @@
 #!/usr/bin/env bash
 set -x
+set -e
 
 IS_COVR=$( python -c "print 'yes' if 'code-coverage' in '$JOB_NAME' else 'no'" )