[1.4.x] Refs #7028 - Fixed clearRawId()' wasn't clearing neither the label (__unicode__ of the related object)
nor the input value.
[1.4.x] Refs #7028 - Fixed `Clear' button malfunction in admin raw_id fields.

The Javascript function `clearRawId()' wasn't clearing neither the label
(__unicode__ of the related object) nor the input value.
Merge branch 'ticket_7028_1_4' of github.com:Starou/django into ticket_7028_1_4
Merge branch 'ticket_7028_1_4' into fcms_1_4_x