fs getfid defaults to '.', like other path-related commands

fs getfid defaults to '.', like other path-related commands

I noticed that all of the other commands that accept a list of paths
use the SetDotDefault() function to default to ".", when no arguments
are given.  This patch adds that call to getfid, making it more
consistent with similar commands.

Reviewed-on: http://gerrit.openafs.org/3008
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Jeffrey Altman <jaltman@openafs.org>
Reviewed-by: Derrick Brashear <shadow@dementia.org>
(cherry picked from commit c77ac5ce976b6f3e5a13a3f739ddbb6e32a177b1)
Change-Id: I94ada76f835ccd01e2061034bd6585d6f1d5dccb
Reviewed-on: http://gerrit.openafs.org/3231