rx: Remove unreachable debug statement

rx: Remove unreachable debug statement

ReceivePacket has a dpf which is conditional on the packet having a
zero callnumber. However, just before we reach this debug statement,
we always return if the header doesn't have a call number included.

So, the debug statement can never run. Just remove it, as it's
potentially confusing.

Change-Id: I5fad9f39c9a0c4aac50853aaf4f853b9f7715e61
Reviewed-on: http://gerrit.openafs.org/8295
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Jeffrey Altman <jaltman@your-file-system.com>
Reviewed-by: Derrick Brashear <shadow@your-file-system.com>