Found out a good number of NT_STATUS_IS_ERR used the wrong way.

Found out a good number of NT_STATUS_IS_ERR used the wrong way.
As abartlet rememberd me NT_STATUS_IS_ERR != !NT_STATUS_IS_OK

This patch will cure the problem.
Working on this one I found 16 functions where I think NT_STATUS_IS_ERR() is
used correctly, but I'm not 100% sure, coders should check the use of
NT_STATUS_IS_ERR() in samba is ok now.

Simo.
(This used to be commit c501e84d412563eb3f674f76038ec48c2b458687)