try a different way to fix Travis

Author: aadrian

.travis.yml

@@ -16,6 +16,10 @@ before_cache:
   - rm -f $HOME/.gradle/caches/modules-2/modules-2.lock
   - rm -fr $HOME/.gradle/caches/*/plugin-resolution/
 
+# avoid calling gradle assemble
+install:
+    - true
+
 cache:
   directories:
     - $HOME/.m2