bisect: call 'clear_commit_marks_all()' in 'bisect_next_all()'

As there can be other revision walks after bisect_next_all(),
let's add a call to a function to clear all the marks at the
end of bisect_next_all().

Mentored-by: Christian Couder <chriscool@tuxfamily.org>
Signed-off-by: Miriam Rubio <mirucam@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
diff --git a/bisect.c b/bisect.c
index d42a3a3..c6aba2b 100644
--- a/bisect.c
+++ b/bisect.c
@@ -1082,6 +1082,8 @@
 		  "Bisecting: %d revisions left to test after this %s\n",
 		  nr), nr, steps_msg);
 	free(steps_msg);
+	/* Clean up objects used, as they will be reused. */
+	clear_commit_marks_all(ALL_REV_FLAGS);
 
 	return bisect_checkout(bisect_rev, no_checkout);
 }