fix spelling mistake stib -> stub
fix spelling mistake stib -> stub

hobodave/webmock,bblimke/webmock,VincentZhao/webmock,hilben/webmock,xuwupeng2000/webmock,spjsschl/webmock,davidbegin/webmock,sinisterstuf/webmock,maruware/webmock,arronmabrey/webmock,Omnihuron/webmock,taiki45/webmock,henrik/webmock,avantcredit/webmock