fix gxx installation

Author: pythoneer

.travis.yml

@@ -3,8 +3,8 @@ before_install:
     - sudo add-apt-repository --yes ppa:ubuntu-toolchain-r/test
     - sudo apt-get update -qq
     - sudo apt-get install -qq qt5-qmake qtbase5-dev qtdeclarative5-dev libqt5webkit5-dev libsqlite3-dev libx11-dev libxtst-dev
-    - if [ "$CXX" = "g++" ]; then sudo apt-get install -qq g++-4.8; fi
-    - if [ "$CXX" = "g++" ]; then export CXX="g++-4.8" CC="gcc-4.8"; fi
+    - sudo apt-get install -qq g++-4.8
+    - export CXX="g++-4.8" CC="gcc-4.8"
 script:
     - g++ --version
     - gcc --version