make abrt-uefioops.service conditional on /sys/fs/pstore being populated

Signed-off-by: Jakub Filak <jfilak@redhat.com>
abrt-harvest-uefioops.in: test for abrtd after testing for pstore, not before

If I'm reading this script right, this seems to make sense. At least this way, if /sys/fs/pstore does not exist at all, we'll exit 0 before we sleep for 1 second for no good reason.

Signed-off-by: Jakub Filak <jfilak@redhat.com>
systemd units: start services only if it make sense

Thanks Lennart Poettering <lpoetter@redhat.com>

Related to rhbz#963182

Signed-off-by: Jakub Filak <jfilak@redhat.com>