upserver: Don't overflow file and hostname buffers

If the user specifies a ridiculously long command line, don't
overflow the filename or hostname buffers with what they supply.

Caught by coverity (#985911)

Change-Id: Ia73f9fb94491f5691358eec1d13dbdd2651a604c
Reviewed-on: http://gerrit.openafs.org/9546
Reviewed-by: Jeffrey Altman <jaltman@your-file-system.com>
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Derrick Brashear <shadow@your-file-system.com>
bucoord: restore requires server and partition

The VolRestoreCmd sub command requires that the user specifies
the server and partition - calls which don't do so won't get past
libcmd. Don't check again in the handler that they have been supplied,
as it confuses things.

Caught by coverity (#985953)

Change-Id: Id4548c117b677bd2048744ade8fd91bb15e0e35e
Reviewed-on: http://gerrit.openafs.org/9547
Reviewed-by: Derrick Brashear <shadow@your-file-system.com>
Reviewed-by: Jeffrey Altman <jaltman@your-file-system.com>
Tested-by: BuildBot <buildbot@rampaginggeek.com>
butc: Init volheader before using it for hton

When converting a volume header from host to network order, make
sure that any unused fields in the structure are zero'd, so we don't
end up filling them with stack garbage in the network version of
the structure.

Caught by coverity (#985956)

Change-Id: I3e039ffcb102a97afeb0e2223de12523f53b0a67
Reviewed-on: http://gerrit.openafs.org/9548
Reviewed-by: Derrick Brashear <shadow@your-file-system.com>
Reviewed-by: Jeffrey Altman <jaltman@your-file-system.com>
Tested-by: BuildBot <buildbot@rampaginggeek.com>