[TravisCI] lock-on to libtorrent-rasterbar 1.0.9 version

.travis.yml

@@ -118,7 +118,10 @@ install:
   - |
     if [ "$TRAVIS_OS_NAME" = "osx" ]; then
       # dependencies
-      brew update > /dev/null && brew install colormake ccache libtorrent-rasterbar ;
+      brew update > /dev/null ;
+      brew install colormake ccache ;
+      # libtorrent-rasterbar 1.0.9
+      brew install https://raw.githubusercontent.com/Homebrew/homebrew-core/477d5060fa093883204d70323965375353e03084/Formula/libtorrent-rasterbar.rb ;
 
       # Qt
       if [ "$qt" = 4 ]; then brew install qt && ln -s /usr/local/Cellar/qt/4.8.7_2/plugins /usr/local ; fi ;