Fixed issues found by winapi_check.

diff --git a/server/registry.c b/server/registry.c
index e4bcf21..f22ab3c 100644
--- a/server/registry.c
+++ b/server/registry.c
@@ -1241,12 +1241,12 @@
     WCHAR *p;
     int res;
     int len = strlen(name) * sizeof(WCHAR);
-    if (!get_file_tmp_space( info, len )) return NULL;
+    if (!get_file_tmp_space( info, len )) return 0;
 
     if ((res = parse_strW( (WCHAR *)info->tmp, &len, name, ']' )) == -1)
     {
         file_read_error( "Malformed key", info );
-        return NULL;
+        return 0;
     }
     for (p = (WCHAR *)info->tmp; *p; p++) if (*p == '\\') break;
     *p = 0;