Merge pull request diffblue#281 from hannes-steffenhagen-diffblue/use_jdk8_on_osx

Make OSX use jdk8 in travis builds

Author: chrisr-diffblue

.travis.yml

@@ -115,6 +115,8 @@ jobs:
     - stage: Test different OS/CXX/Flags
       os: osx
       sudo: false
+      jdk: openjdk8
+      osx_image: xcode8.3
       compiler: clang
       cache: ccache
       before_install:
@@ -293,6 +295,8 @@ jobs:
     # cmake build on OSX, using default clang
     - stage: Test different OS/CXX/Flags
       os: osx
+      jdk: openjdk8
+      osx_image: xcode8.3
       compiler: clang
       cache: ccache
       before_install: