Calling /api/state with no printer attached causes server 500.

[foofoodog]

Running this from source with no printer attached. Might not be a valid scenario. Still, the thing blows up and all other code in that routine has "is not None" checks so I figure it is an omission.

Need to check self._temp is not None before iterating tool in self._temp.keys() in printer.py getCurrentTemperatures.

if self._temp is not None:
    for tool in self._temp.keys():

@GitIssueBot I love cookies

[foosel]

Fixed via backported commit from devel branch (please mention the branch/version next time, thanks), see 684d12e