doc: voldump manpage fixes

Add missing documentation for the -time and -help options.

Change-Id: I04ca0fe6d4a5c298415e450a38a19b719dca4800
Reviewed-on: http://gerrit.openafs.org/10391
Reviewed-by: Derrick Brashear <shadow@your-file-system.com>
Tested-by: Derrick Brashear <shadow@your-file-system.com>
doc: kaserver manpage fixes

 - Add missing -rxbind

 - Add missing -crossrealm

 - Fix synopsis formatting, so option arguments are on the same line
   as the option name

Change-Id: I8c73d0f14396aad83651c3037fde1137d83e6692
Reviewed-on: http://gerrit.openafs.org/10392
Reviewed-by: Derrick Brashear <shadow@your-file-system.com>
Tested-by: Derrick Brashear <shadow@your-file-system.com>