Inconsistent behavior when restoring default session and language

Hello,

while digging further into the lightdm sources to address bug #1069863, I stumbled over another inconsistency regarding last session and locale management similar to bug #1068853.

While bug #1068853 explains that session and language are not consistently stored to ${HOME}/.dmrc, I figured out that lightdm actually doesn't consistently loads the default language from AccountsService while it does for dmrc. To be more specific, lightdm never stores the language to AccountsService, however it always stores it to ${HOME}/.dmrc which means that lightdm can only restore the last language when using the dmrc mechanism.

I am not really sure whether this was intentional, but it is for very sure very confusing and inconsistent. If lightdm detects that AccountsService is available and wants to restore the last session and language from this resource, it should do so and not simply ignore the language stored through AccountsService.

I'm attaching a patch which fixes the behavior and restores both the last session and language consistently from AccountService.

Cheers,

Adrian