ptserver: Zero ubik header before writing to it

When using pt_util's ubik shim, if we're creating a new ubik label
make sure to zero the whole structure before writing it out to disk.
Otherwise we get a shorts worth of stack garbage in the resulting
file.

Caught by coverity (#986010)

Change-Id: I0abb8b7968d4f25c97dc0927d63dd01099b829b7
Reviewed-on: http://gerrit.openafs.org/9274
Reviewed-by: Derrick Brashear <shadow@your-file-system.com>
Reviewed-by: Chas Williams - CONTRACTOR <chas@cmf.nrl.navy.mil>
Reviewed-by: Jeffrey Altman <jaltman@your-file-system.com>
Tested-by: BuildBot <buildbot@rampaginggeek.com>
volser: Catch EOFs when reading dumps

When reading a standard tag, make sure and catch an EOF error
from iod_getc. Otherwise we'll end up trying to parse 0xFF as a
tag length.

Caught by coverity (#985603)

Change-Id: Iae0b1bf71ed495b4f454975a1bfe3aef8fca3e9e
Reviewed-on: http://gerrit.openafs.org/9275
Reviewed-by: Derrick Brashear <shadow@your-file-system.com>
Reviewed-by: Chas Williams - CONTRACTOR <chas@cmf.nrl.navy.mil>
Reviewed-by: Jeffrey Altman <jaltman@your-file-system.com>
Tested-by: BuildBot <buildbot@rampaginggeek.com>