Fix gems on travis for ruby < 2.0.0
Fix gems on travis for ruby < 2.0.0

vhtien/gooddata-ruby,Seikitsu/gooddata-ruby,fluke777/gooddata-ruby,fluke777/gooddata-ruby,lubosvesely/gooddata-ruby,vhtien/gooddata-ruby,Seikitsu/gooddata-ruby,fluke777/gooddata-ruby,lubosvesely/gooddata-ruby,vhtien/gooddata-ruby,lubosvesely/gooddata-ruby,Seikitsu/gooddata-ruby