Fixing boolean check for stats (Issue #1270)

eaf1a69 half fixed the issue with connection problems.

The check for $xml == false is always true, and so the stat_id and
stat_key returned by the tracker are never saved on the database. This
never lets new deployments get their stats started.
Merge pull request #1273 from ditorelo/1270

Fixing boolean check for stats (Issue #1270)