On Ruby 1.8, Only require URI methods from Rack if they are not already loaded
On Ruby 1.8, Only require URI methods from Rack if they are not already loaded

Closes #619

karmi/retire,mavenlink/retire,ChapterMedia/tire,zaharpecherin/retire,Telmate/tire,doximity/tire,fabn/retire,brijeshgpt7/retire,rubydubee/retire,dbose/retire,HenleyChiu/tire,iamrahulroy/retire,tklee/tire_shiphawk,1776/tire,elbuo8/retire