secur32: Check if the table exist before using it

[André Hentschel]

might fix the crash in http://test.winehq.org/data/32c36b7505e59d29c25e193e598e9edf8496066b/solaris_fg-solex11-vm/secur32:ntlm.html
---
 dlls/secur32/wrapper.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/dlls/secur32/wrapper.c b/dlls/secur32/wrapper.c
index dabd90f..a257420 100644
--- a/dlls/secur32/wrapper.c
+++ b/dlls/secur32/wrapper.c
@@ -462,7 +462,7 @@ SECURITY_STATUS WINAPI DeleteSecurityContext(PCtxtHandle phContext)
         SecurePackage *package = (SecurePackage *)phContext->dwUpper;
         PCtxtHandle ctxt = (PCtxtHandle)phContext->dwLower;
 
-        if (package && package->provider &&
+        if (package && package->provider && package->provider->fnTableW &&
          package->provider->fnTableW.DeleteSecurityContext)
             ret = package->provider->fnTableW.DeleteSecurityContext(ctxt);
         else
-- 

Best Regards, André Hentschel