Update vex install script to use ssh url for git to allow easier changes and also use because of sh problems on OS X.
Update vex install script to use ssh url for git to allow easier changes and also use because of sh problems on OS X.

chubbymaggie/codereason,chubbymaggie/codereason,trailofbits/codereason,terry2012/codereason,terry2012/codereason,terry2012/codereason,trailofbits/codereason,trailofbits/codereason,chubbymaggie/codereason,chubbymaggie/codereason,terry2012/codereason,trailofbits/codereason,chubbymaggie/codereason,terry2012/codereason,trailofbits/codereason