vol-salvage: calloc volume summary structs
Calloc volume summary structs instead of malloc'ing them, in
vol-salvage.c. This way, new fields added to struct VolumeSummary will
be known to be zeroed by default, without needing to update all of the
allocating callers.
Change-Id: I8c647cd9dec7aaf14183452126049323859ac7a3
Reviewed-on: http://gerrit.openafs.org/4117
Reviewed-by: Simon Wilkinson <sxw@inf.ed.ac.uk>
Reviewed-by: Derrick Brashear <shadow@dementia.org>
Tested-by: BuildBot <buildbot@rampaginggeek.com>