extensionUtils: Check version variable for undefined first

Avoid a warning message when trying to access requiredArray[2] by
checking if its undefined first.

https://gitlab.gnome.org/GNOME/gnome-shell/merge_requests/96

js/misc/extensionUtils.js

@@ -165,8 +165,8 @@ function versionCheck(required, current) {
         let requiredArray = required[i].split('.');
         if (requiredArray[0] == major &&
             requiredArray[1] == minor &&
-            (requiredArray[2] == point ||
-             (requiredArray[2] == undefined && parseInt(minor) % 2 == 0)))
+            ((requiredArray[2] === undefined && parseInt(minor) % 2 == 0) ||
+             requiredArray[2] == point))
             return true;
     }
     return false;