Fix 'clean'-target in Makefile of master

The 'clean'-target used the JENKINS_HOME variable. The variable
reference did not use curly braces, which led to an error.

Change-Id: I5602b12eb27be000e55aa6fc1353d9522a3f6ba7
1 file changed
tree: 0a03cf5b8af91e8486e7e7c15caf75977c7e0bdb
  1. jenkins/
  2. jenkins-docker/
  3. worker/
  4. .gitignore