remove an unnecessary ppa from travis

Because we are including saucy now (to get SDL mixer 1.2.12),
adding this test ppa is unnecessary (saucy has g++-4.8), and it
can only serve to confuse / cause us to accidentally get
mismatching lib versions, so I remove it

.travis.yml

@@ -28,7 +28,6 @@ before_install:
     - if [ "$CXX" = "g++" ]; then export WML_TESTS=false; fi
     - if [ "$CXX" = "g++" ]; then export PLAY_TEST=false; fi
     - if [ "$CXX" = "g++" ]; then export CHECK_UTF8=false; fi
-    - if [ "$CXX" = "g++" ]; then time sudo add-apt-repository ppa:ubuntu-toolchain-r/test -y; fi
 
 install:
     - sudo add-apt-repository -y "deb http://archive.ubuntu.com/ubuntu/ saucy main universe"