Update key handling:

Update key handling:
o use proper api for setting/deleting keys instead of depending
  on key indices
o check mac address to decide whether a key is unicast or group/global
o check set_tx on key set to decide whether a group/global key should
  also be marked as default
o explicitly set IEEE80211_KEY_GROUP flag for group keys instead of
  depending on kernel auto-add kludge

With the above changes static wep key handling works.

Reviewed by:	avatar
Approved by:	re (scottl)