do not use bash profile

.travis.yml

@@ -670,7 +670,7 @@ before_install: |
       echo $ENABLE_HEADLESS > headless.enabled
 
       if [ -n "$IS_OSX" ]; then
-        echo 'export PATH="/usr/local/sbin:$PATH"' >> ~/.bash_profile
+        export PATH="/usr/local/sbin:$PATH"
         TAPS="$(brew --repository)/Library/Taps"
         if [ -e "$TAPS/caskroom/homebrew-cask" -a -e "$TAPS/homebrew/homebrew-cask" ]; then
             rm -rf "$TAPS/caskroom/homebrew-cask"