s4 smdb standard: Limit processes forked on accept.

s4 smdb standard: Limit processes forked on accept.

Limit the number of processes started by the standard model on accept.
For those services that support fork on accept, the standard model forks
a new process for each new connection. This patch limits the number of
processes to the value specified in 'max smbd processes', a value of
zero indicates that there is no limit on the number of processes that
can be forked.

Signed-off-by: Gary Lockyer <gary@catalyst.net.nz>
Reviewed-by: Andrew Bartlett <abartlet@samba.org>