XCVR2450 fix announcement

To users having difficulty with the XCVR2450 daughterboard.

A bug was found that effects the XCVR2450 in transceiver applications,
especially tunnel.py. A fix has been applied to the host code in r10853
of the trunk. This fix is for XCVR2450 + USRP (does not apply to the
USRP2).

Testers are welcome.

Thanks,
-Josh