Fixed a warning

git-svn-id: https://svn.code.sf.net/p/rathena/svn/trunk@10004 54d463be-8e91-2dee-dedb-b68131a5f0ec

src/common/mapindex.c

@@ -43,7 +43,7 @@ int mapindex_addmap(int index, const char *name)
 	}
 	if ((ext = strstr(map_name, ".")) != NULL) { // Remove extension
 		length = ext-map_name;
-		sprintf(ext, "\0");
+		*ext = '\0';
 	}
 
 	if (indexes[index].length)