[Samba] Internal DNS stops forwarding

[felix at epepm.cupet.cu]

> Ok we found some bugs that could lead to a frozen dns server can you try
> rc2?
> Matthieu.

Happened again with rc2 but found that at the same time this error shows
every second:

[2012/10/05 09:01:39,  0]
../source4/smbd/process_single.c:56(single_accept_connection)
  single_accept_connection: accept: NT_STATUS_TOO_MANY_OPENED_FILES

After restarting everything is OK, but it happened yesterday though I
didn't notice it was at the same time the dns error and this too many
opened files.