RX: Remove allocation counters

RX: Remove allocation counters

Remove the osi_alloccnt and osi_allocsize counters, and the associated
osi_alloc_mutex. These counters are pretty useless since nothing looks
at them, and their use of a mutex requires Rx to be initialized before
XDR can be used. Removing them lifts this restriction.

Change-Id: I22fa1335b6d34675d37cca41a2c393b9c20d3d24
Reviewed-on: http://gerrit.openafs.org/4478
Reviewed-by: Simon Wilkinson <sxw@inf.ed.ac.uk>
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Derrick Brashear <shadow@dementia.org>