afsd: Parse cacheinfo during argument parsing

Currently we parse cacheinfo in afsd_run, when the client is
initialized and started. Parsing cacheinfo can change
afsd_cacheMountDir, however, which may be of interest to afsd.o users;
in particular, libuafs exposes this via uafs_MountDir(). This means
that if a mount dir is not explicitly specified in the libcmd
arguments to afsd, a libuafs-using program will see the mountpoint as
the empty string if it is queried after afsd_parse but before
afsd_run. For afsd.fuse, this causes the cryptic error message:

    fuse: bad mount point `': No such file or directory

since the mountpoint is the empty string if it is not specified
explicitly on the command line.

To fix this, move cacheinfo parsing to effectively near the end of
afsd_parse, so the mountpoint is calculated in afsd_parse().

Reviewed-on: http://gerrit.openafs.org/6400
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Derrick Brashear <shadow@dementix.org>
(cherry picked from commit af218dee6c517f4636a18c681bff6f1212a7d9c0)

Change-Id: Ibd087f52c9a6f1d98614f4fdbbc5b92ea0806506
Reviewed-on: http://gerrit.openafs.org/9453
Reviewed-by: Andrew Deason <adeason@sinenomine.net>
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Michael Meffie <mmeffie@sinenomine.net>
Reviewed-by: Benjamin Kaduk <kaduk@mit.edu>
Reviewed-by: Stephan Wiesand <stephan.wiesand@desy.de>