Revert "s4-libcli: Remove unused finddcs_nbt"

Revert "s4-libcli: Remove unused finddcs_nbt"

This reverts commit 06c90cb6f55701effa4cbafaf189a4de8471949b.

There is genuine interest in using this currently unused code, so put
it back into the tree to avoid folks having to rewrite it.

It should be carefully hooked back into libnet at some point, and
possibly told how to talk to the s3 nmbd socket if nbt_server isn't
running.

The wscript patches are skipped, due to the way the extra
dep interacted with the build system.  When used, this will be resolved.

Andrew Bartlett