Fix "warning: instance variable @query_params not initialized" warning
Fix "warning: instance variable @query_params not initialized" warning

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