Revert root check (#412)

Signed-off-by: Riley Laine <rlaine@slack-corp.com>

go/vt/servenv/servenv.go

@@ -106,7 +106,7 @@ func Init() {
 	// Once you run as root, you pretty much destroy the chances of a
 	// non-privileged user starting the program correctly.
 	if uid := os.Getuid(); uid == 0 {
-		//		log.Exitf("servenv.Init: running this as root makes no sense")
+		log.Exitf("servenv.Init: running this as root makes no sense")
 	}
 
 	// We used to set this limit directly, but you pretty much have to