Remove only master from .travis.yml

.travis.yml

@@ -6,10 +6,6 @@ jdk:
 os:
   - linux
 
-branches:
-  only:
-    - master
-
 before_cache:
   - rm -f $HOME/.gradle/caches/modules-2/modules-2.lock
 cache:
@@ -17,4 +13,4 @@ cache:
     - $HOME/.gradle/caches/
     - $HOME/.gradle/wrapper/
 
-script: ./gradlew build
+script: ./gradlew build