EXCLUDE_UNENCRYPTED bit in the WI_RID_P2_ENCRYPTION value if we are
in shared key mode. Symbol cards, just to be different, supposedly
always want the EXCLUDE_UNENCRYPTED bit set (confirmed with the
Linux orinoco and spectrum24 drivers).
* Flesh out the Host-AP WEP transmit side. Note this does not yet
work properly; the frame as seen by the receiver FCS's incorrectly.
Both changes from OpenBSD. Not confirmed whether or not Host-AP WEP
works with OpenBSD (mail sent to millert).