vos: Initialise total counters

vos: Initialise total counters

When VolumeStats_int calls DisplayFormat, it isn't interested in
the total counters it provides. So, it doesn't both initialising the
variables it passes in to hold these counters - garbage in, garbage out.

However, this shows up as an uninitialises variable warning, so set them
all to 0 to keep clang happy.

Caught by clang-analyzer

Change-Id: Ia3e1eadde6eac6fa924a4ff9ad566c5c50f9ff40
Reviewed-on: http://gerrit.openafs.org/7095
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Derrick Brashear <shadow@dementix.org>