advapi32: Fix cred domain according to tests.

dlls/advapi32/cred.c

@@ -1820,6 +1820,9 @@ BOOL WINAPI CredWriteW(PCREDENTIALW Credential, DWORD Flags)
             SetLastError(ERROR_BAD_USERNAME);
             return FALSE;
         }
+
+        Credential->CredentialBlobSize = 0;
+        Credential->CredentialBlob = NULL;
     }
 
 #ifdef __APPLE__

dlls/advapi32/tests/cred.c

@@ -202,9 +202,7 @@ static void check_blob(int line, DWORD cred_type, PCREDENTIALA cred)
 {
     if (cred_type == CRED_TYPE_DOMAIN_PASSWORD)
     {
-        todo_wine
         ok_(__FILE__, line)(cred->CredentialBlobSize == 0, "expected CredentialBlobSize of 0 but got %d\n", cred->CredentialBlobSize);
-        todo_wine
         ok_(__FILE__, line)(!cred->CredentialBlob, "expected NULL credentials but got %p\n", cred->CredentialBlob);
     }
     else