Removed composer-asset-plugin from travis

Author: Alexey Shishkov

.travis.yml

@@ -10,7 +10,6 @@ cache:
 
 install:
   - composer self-update && composer --version
-  - travis_retry composer global require "fxp/composer-asset-plugin:~1.4"
   - export PATH="$HOME/.composer/vendor/bin:$PATH"
   - travis_retry composer install --prefer-dist --no-interaction