This commit make winbindd copy winbindd_idmap.tdb into idmap.tdb on the

This commit make winbindd copy winbindd_idmap.tdb into idmap.tdb on the
first run if idmap.tdb is not found, and then eventually convert it to the
new format.
This is done to unify winbind and idmap databases and to make a backup of
winbindd_idmap.tdb in case you want to downgrade (of course it will not be
updated).
This is needed because idmap.tdb contains also local mappings, not only
foreign domains mappings.

Added some other fixes/improvements

Simo.
(This used to be commit cf17261519fd8775500f9b9d6caa2bc462e04633)