Windows: Restructure cm_LookupInternal addition of Freelance entries

Windows: Restructure cm_LookupInternal addition of Freelance entries

cm_LookupInternal creates Freelance mount points and symlinks
when queries cannot be found in the Freelance root.afs directory.
If the search name is a full cell name for which vldb information
can be obtained, then a mount point is added.  If the search name
is a left-most substring or the full cell name with a dot appended
to it, then a symlink was created.  This approach created a very
poluted Freelance name space.

This patchset makes the following changes:

 1. Do not create symlinks with a dot appended to the cellname

 2. Do not create symlinks where the left-most substring is not
    a full dot separated component of the cellname.

 3. Permit lookups to succeed when we would have created a
    symlink in the past without creating the symlink.

LICENSE MIT

Change-Id: I4573a2f13d4843878c3f5efc546df29a5023accc
Reviewed-on: http://gerrit.openafs.org/1894
Reviewed-by: Jeffrey Altman <jaltman@openafs.org>
Tested-by: Jeffrey Altman <jaltman@openafs.org>