Update INSTALL.md
Update INSTALL.md

fix 4. Roswell as a Testing Environment (Travis CI and Coverall) url
guicho271828/roswell,roswell/roswell,snmsts/roswell,snmsts/roswell,guicho271828/roswell,roswell/roswell,snmsts/roswell,snmsts/roswell,roswell/roswell,guicho271828/roswell,guicho271828/roswell,roswell/roswell