Fix two more small memory leaks on REHASH.

Now we are at zero leaks again with ASan, or so it seems.

src/modules/history_backend_mem.c

@@ -235,6 +235,7 @@ static void setcfg(struct cfgstruct *cfg)
 
 static void freecfg(struct cfgstruct *cfg)
 {
+	safe_free(cfg->masterdb);
 	safe_free(cfg->directory);
 	safe_free(cfg->db_secret);
 }

src/modules/targetfloodprot.c

@@ -117,6 +117,8 @@ MOD_LOAD()
 
 MOD_UNLOAD()
 {
+	safe_free(channelcfg);
+	safe_free(privatecfg);
 	return MOD_SUCCESS;
 }