Bug#874529: What debug is needed ?

[Jean Tourrilhes]

Severity: important

	This bug made one of our workstation unusable, and preventing
the upgrade of other workstations (stuck at Jessie). I'm willing to
help debug that issue, but somebody needs to point out what
information and/or log is needed.
	Honestly, I'm surprised that nobody tested that GDM3 supported
multiple users, that seems like one of the core functions.
	I'm looking forward to help you guys...
	Regards,

	Jean