path: use '===' instead of '==' for comparison

Per: https://github.com/joyent/node/pull/7554

Originally submitted by @stites

PR-URL: https://github.com/nodejs/node/pull/2388
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Roman Reiss <me@silverwind.io>

lib/path.js

@@ -277,7 +277,7 @@ win32.relative = function(from, to) {
     }
   }
 
-  if (samePartsLength == 0) {
+  if (samePartsLength === 0) {
     return to;
   }