Take a shot at fixing the travis cache.

Author: nedtwigg

.travis.yml

@@ -7,6 +7,7 @@ services:
 before_cache:
   - rm -f  $HOME/.gradle/caches/modules-2/modules-2.lock
   - rm -fr $HOME/.gradle/caches/*/plugin-resolution/
+  - rm -fr $HOME/.gradle/caches/*/*/*.lock
 cache:
   directories:
   - $HOME/.gradle/caches/