Windows: Update fs newcell and add VIOCNEWCELL2

Windows: Update fs newcell and add VIOCNEWCELL2

The Windows version of "fs newcell" did not accept any parameters
and behaved quite differently from the Unix version.  Instead of
permitting new cell information to be added, the Windows version
simply forced the existing cell information to be reacquired.

This update adds a new pioctl, VIOCNEWCELL2, to support the
implementation of a Unix-style "fs newcell".  The functionality
added here differs from the Unix version in the following ways:

 1. "fs newcell" with no arguments is still accepted
    in order to maintain compatibility with prior Windows
    behavior.

 2. "fs newcell -cell <cell> -dns" instructs the cache manager
    to add the new cell but obtain the vldb server info from
    DNS.

 3. "fs newcell -cell <cell> ... -registry" instructs the cache
    manager to add the new cell and also save the cell configuration
    data in the registry for use the next time the service restarts.

 4. The -vlport and -fsport options are accepted although the
    -fsport value is currently unsupported by the cache manager.

LICENSE MIT

Change-Id: If62cc8e1c6cc8ba2defb4cd72dae8a87b4d915e0
Reviewed-on: http://gerrit.openafs.org/2080
Reviewed-by: Jeffrey Altman <jaltman@openafs.org>
Reviewed-by: Derrick Brashear <shadow@dementia.org>
Tested-by: Jeffrey Altman <jaltman@openafs.org>