Fix autopromote
It seems that the autopromote function fails if the user registration date is unknown/empty/null which happens at Wikimedia for a lot of old users.
Attached patch based on a proposal by an anon reader (see URL).
Version: unspecified
Severity: normal
URL: http://de.wikipedia.org/w/index.php?title=Wikipedia_Diskussion:Gesichtete_Versionen&oldid=50505207#Benutzer-Neuanmeldungsdatum_und_automatisch_zum_.E2.80.9ESichter.E2.80.9C_werden_passen_nicht_ganz_zueinander
Attached: