ntdll: Fix printing NULL strings.

[Francois Gouget]

---

This fixes a crash that occurred in the conformance tests on my Solaris 
VMs when tracing was turned on.

 dlls/ntdll/atom.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/dlls/ntdll/atom.c b/dlls/ntdll/atom.c
index 3789567..304b7f6 100644
--- a/dlls/ntdll/atom.c
+++ b/dlls/ntdll/atom.c
@@ -164,7 +164,7 @@ NTSTATUS WINAPI RtlQueryAtomInAtomTable( RTL_ATOM_TABLE table, RTL_ATOM atom, UL
     }
 
     TRACE( "%p %x -> %s (%x)\n",
-           table, atom, len ? debugstr_wn(name, wlen / sizeof(WCHAR)) : NULL, status );
+           table, atom, len ? debugstr_wn(name, wlen / sizeof(WCHAR)) : "(null)", status );
     return status;
 }
 
-- 
1.7.5.4