fix test_download_md5 test
fix test_download_md5 test

thaddeustaylor/catkin,jack-oquin/catkin,harmishhk/catkin,ros/catkin,wkentaro/catkin,harmishhk/catkin,shyamalschandra/catkin,asmodehn/catkin,scpeters/catkin,jack-oquin/catkin,wkentaro/catkin,wkentaro/catkin,beni55/catkin,harmishhk/catkin,jack-oquin/catkin,shyamalschandra/catkin,thaddeustaylor/catkin,ros/catkin,thaddeustaylor/catkin,beni55/catkin,ros/catkin,scpeters/catkin,beni55/catkin,shyamalschandra/catkin,scpeters/catkin,asmodehn/catkin,asmodehn/catkin