rx: Remove rx_waitingForPacket

Commit f43c2f4412d670ce1131dc429cb43302352df3e4 introduced
rx_waitingForPacket.  Given its current usage, I can't see any
functionality.

It looks like this might have been the result of merging a renamed
rx_waitForPacket from another development branch?

Reviewed-on: http://gerrit.openafs.org/10981
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Jeffrey Altman <jaltman@your-file-system.com>
(cherry picked from commit be236140f72fc51e111898abc896f93cc505fac7)

Change-Id: Ib1be9031bc217183f1997b6d79455e1693fa7c21
Reviewed-on: http://gerrit.openafs.org/11219
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Perry Ruiter <pruiter@sinenomine.net>
Reviewed-by: Benjamin Kaduk <kaduk@mit.edu>
Reviewed-by: Stephan Wiesand <stephan.wiesand@desy.de>