Repo: Only update package.json with nextVersion

Fixes gh-57
Closes gh-58

Author: jzaefferer

lib/repo.js

@@ -259,8 +259,8 @@ Release.define({
 		Release.exec( "git checkout " + Release.branch,
 			"Error checking out " + Release.branch + " branch." );
 
-		// Update all JSON versions
-		Release._setVersion( Release.nextVersion );
+		// Update only canonical version
+		Release._versionJSON( "package.json", Release.nextVersion );
 
 		console.log( "Committing version update..." );
 		Release.exec( "git commit -am 'Build: Updating the " + Release.branch +