Fail print jobs targeted to unavailable services.

It is possible that a print job is scheduled for handling, i.e. it is
queued, after the target print service is uninstalled or disabled.
In case like this we fail the print job with an appropriate error
message. Now the user can cancel the job when he/she sees the notification
or the status in the print settings. Trying to restart such a job will
end up failing it again with the same error message. So the user will
just have to canel the print job.

This apporach quarantees that the user is informed for the failure and
also is much simpler than trying to update the UI when print job's
target serivce is uninstalled. For example, the settings UI has to
be updated as well as the notifications. Also due to the async nature
of the system this we cannot completely avoid having a restart option
for a print job whose target service is gone. This scenario is very
unlikely but still we have to handle it.

bug:11012251

Change-Id: Id8c8c3cff75e0b6325552676b130ff1406edc069