winbind: Remove noisy error message in wb_open_internal_pipe()

winbind: Remove noisy error message in wb_open_internal_pipe()

Before merging the s4 and s3 RPC servers the make_internal_rpc_pipe_p()
function did not fail when the requested interface was not registered in
the calling process because it did not check the return value of
rpc_srv_get_pipe_cmds(). If the interface was not registed, the pointer
to the interface functions was NULL and later, when dispatching a call,
rpcint_dispatch() returned NT_STATUS_RPC_PROCNUM_OUT_OF_RANGE in this
case.

After merging the RPC servers, the rpc_pipe_open_internal() function
will return NT_STATUS_RPC_INTERFACE_NOT_FOUND if the interface is not
registered in the calling process. This causes a noisy error message in
winbind when it tries to open the dssetup pipe to the primary domain and
it is not an AD domain.

The callers of wb_open_internal_pipe() when connecting to the domain
already logs the error at level greather or equal to five. This commit
moves the dupplicated and noisy error message at level zero from
wb_open_internal_pipe() to its callers outside winbindd_cm.c.

This error can be seen in winbindd logs of ad_member and nt4_member test
environments.

[2021/03/01 16:49:38.486004,  0, pid=12456] ../../source3/winbindd/winbindd_cm.c:1893(wb_open_internal_pipe)
  open_internal_pipe: Could not connect to dssetup pipe: NT_STATUS_RPC_INTERFACE_NOT_FOUND

Signed-off-by: Samuel Cabrero <scabrero@samba.org>
Reviewed-by: Jeremy Allison <jra@samba.org>