libsamba-errors: eliminate dependency on samba-debug

libsamba-errors: eliminate dependency on samba-debug

libsamba-errors is a collection of error codes/descriptions
like strerror(), - it is a set of simple functions converting
error code to string or the like.  However, in one single
place there's a DBG_DEBUG() "call" in errmap_unix.c, in
map_errno_from_nt_status(), which is here for a very long time
(since before samba3, initially with debug level 10).

Drop this debugging info, and eliminate extra dependency.
This makes libsamba-errors independent and self-contained,
with a well-known and stable ABI.

Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
Reviewed-by: Andreas Schneider <asn@samba.org>
Reviewed-by: Pavel Filipenský <pfilipensky@samba.org>