ci: Fixes build matrix for Travis-CI checks

Change-Id: I4f589b3575264ecf5aa85468999836ec44dfa12a
Refs: #3150
diff --git a/.travis.yml b/.travis.yml
index 4c630a1..d9190fd 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -5,12 +5,15 @@
   - osx
 compiler:
   - gcc
-branches:
-  only:
-    - master
+  - clang
+matrix:
+  exclude:
+    - os: linux
+      compiler: clang
+    - os: osx
+      compiler: gcc
 script:
   - if [[ $TRAVIS_OS_NAME == linux ]]; then export NODE_LABELS="Linux Ubuntu Ubuntu-12.04"; fi
   - if [[ $TRAVIS_OS_NAME == osx ]]; then export NODE_LABELS="OSX OSX-10.10"; fi
   - echo $NODE_LABELS
   - ./.jenkins
-