Removed mono dependency for travis

Author: fabienrenaud

.travis.yml

@@ -1,12 +1,7 @@
 dist: trusty
 language: java
 jdk:
-  - oraclejdk8
-before_install:
-  - sudo apt-key adv --keyserver hkp://keyserver.ubuntu.com:80 --recv-keys 3FA7E0328081BFF6A14DA29AA6A19B38D3D831EF
-  - echo "deb http://download.mono-project.com/repo/ubuntu stable-trusty main" | sudo tee /etc/apt/sources.list.d/mono-official-stable.list
-  - sudo apt-get -qq update
-  - sudo apt-get install -y mono-devel 
+  - openjdk8 
 install:
   - ./gradlew assemble