linux+clang+qt5 works now, disable allow_failures

.travis.yml

@@ -19,8 +19,4 @@ notifications:
     on_failure: change
     on_start: false
 matrix:
-  fast_finish: true
-  allow_failures:
-    - compiler: clang
-      os: linux
-      env: QT4=0
+  fast_finish: true
\ No newline at end of file