Windows: GetReparseData UNC path format

When specifying UNC paths for Symlink and UNCLink targets output
the paths using true UNC notation "\\server\..." instead of "\server\...".

Change-Id: I51ecc6578fb0a984a5ad44b1bf1e40556e737465
Reviewed-on: http://gerrit.openafs.org/9426
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Jeffrey Altman <jaltman@your-file-system.com>
Tested-by: Jeffrey Altman <jaltman@your-file-system.com>