Ticket #3150: achown: escape on user list should not accept value.

Open the Advanced chown dialog. Navigate to owner or group, and press
Enter. A dialog enlisting the available usernames or groups appears.

Move up or down in this dialog, then press double Esc or F10.

Actual behavior: The selected value gets accepted, just as if Enter was
pressed.

Expected behavior: The user or group is not changed, as if this dialog
was not opened at all.

Signed-off-by: Andrew Borodin <aborodin@vmail.ru>
Merge branch '3150_achown_list_esc'

* 3150_achown_list_esc:
  Ticket #3150: achown: escape on user list should not accept value.