iwlwifi: report scan completion when abort fail

When we are not able to send abort command to firmware, notify mac80211
that we complete scan, as we will newer do it lately. Check for all
possible errors that low level sending command procedure does not check,
to assure we catch all failures cases.

Patch fix one of the causes of wdev_cleanup_work warning reported at
https://bugzilla.redhat.com/show_bug.cgi?id=593566



Signed-off-by: Stanislaw Gruszka <sgruszka@redhat.com>
Acked-by: Wey-Yi W Guy <wey-yi.w.guy@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>