docs: Fixed error in code sample.

The code sample for GooglePlayServicesUtil.getErrorDialog had an
error, per bug report from the community. Staged the fixed doc to

http://asolovay.mtv:9860/training/location/retrieve-current.html#CheckServices

Aron, it looks like you've edited GooglePlayServicesUtil.java so I
hoped you could give it a +1. If not you, can you suggest someone?

bug: 17009860
Change-Id: Id5cbf13d2b771cfe168f1b4cb1abd5e339f1ac60

docs/html/training/location/retrieve-current.jd

@@ -167,13 +167,12 @@ public class MainActivity extends FragmentActivity {
                     "Google Play services is available.");
             // Continue
             return true;
-        // Google Play services was not available for some reason
+        // Google Play services was not available for some reason.
+        // resultCode holds the error code.
         } else {
-            // Get the error code
-            int errorCode = connectionResult.getErrorCode();
             // Get the error dialog from Google Play services
             Dialog errorDialog = GooglePlayServicesUtil.getErrorDialog(
-                    errorCode,
+                    resultCode,
                     this,
                     CONNECTION_FAILURE_RESOLUTION_REQUEST);