[skip ci] remove useless bowerrc
[skip ci] remove useless bowerrc

Polymer/web-component-tester,sankethkatta/web-component-tester,fearphage/web-component-tester,sankethkatta/web-component-tester,Polymer/tools,fearphage/web-component-tester,fearphage/web-component-tester,hvdb/web-component-tester,Polymer/web-component-tester,Polymer/tools,hvdb/web-component-tester,marcinkubicki/web-component-tester,marcinkubicki/web-component-tester,marcinkubicki/web-component-tester,sankethkatta/web-component-tester,Polymer/tools,Polymer/tools,hvdb/web-component-tester,Polymer/web-component-tester