Repo: Simplify tag commit message to pass guidelines

This is also more consistent with repos where we you 'npm tag', which also
only uses the version number as the commit message.

Fixes gh-33

Author: jzaefferer

lib/repo.js

@@ -184,7 +184,7 @@ Release.define({
 		Release.chdir( Release.dir.repo );
 		console.log( "Committing release artifacts..." );
 		Release.git( "add -f " + paths.join( " " ), "Error adding release artifacts to git." );
-		Release.git( "commit -m 'Tagging the " + Release.newVersion + " release.'",
+		Release.git( "commit -m '" + Release.newVersion + "'",
 			"Error committing release changes." );
 		console.log();