line-range: plug leaking find functions

In `parse_range_funcname()` we may end up allocating a "find function",
but never free it. Fix this.

Signed-off-by: Patrick Steinhardt <[email protected]>
Signed-off-by: Junio C Hamano <[email protected]>

Author: pks-t

line-range.c

@@ -234,6 +234,8 @@ static const char *parse_range_funcname(
 	}
 
 	regfree(&regexp);
+	if (xecfg)
+		xdiff_clear_find_func(xecfg);
 	free(xecfg);
 	free(pattern);