Correctly check -j / -k's values

Check as ':' instead of NULL, as : is the default value of rule_buf_l and rule_buf_r

src/dictstat.c

@@ -100,8 +100,8 @@ void dictstat_read (hashcat_ctx_t *hashcat_ctx)
 
   if (hashconfig->dictstat_disable == true) return;
 
-  if (user_options->rule_buf_l != NULL) return;
-  if (user_options->rule_buf_r != NULL) return;
+  if (*user_options->rule_buf_l != ':') return;
+  if (*user_options->rule_buf_r != ':') return;
 
   HCFILE fp;
 
@@ -192,8 +192,8 @@ int dictstat_write (hashcat_ctx_t *hashcat_ctx)
 
   if (hashconfig->dictstat_disable == true) return 0;
 
-  if (user_options->rule_buf_l != NULL) return 0;
-  if (user_options->rule_buf_r != NULL) return 0;
+  if (*user_options->rule_buf_l != ':') return 0;
+  if (*user_options->rule_buf_r != ':') return 0;
 
   HCFILE fp;