fix hls & dash segments cleanup. #3527

Job	Run time
utest-regression-blackbox-test	9m 38s
multiple-arch-aarch64	22m 38s
multiple-arch-armv7	21m 54s
cygwin64-cache	1m 43s
fast	1s
cygwin64	14m 41s
build-ubuntu16	3m 17s
build-centos7	4m 54s
build-cross-aarch64	5m 12s
build-cross-arm	5m 28s
build-ubuntu18	3m 6s
multiple-arch-amd64	2m 24s
build-ubuntu20	3m 40s
coverage	3m 46s
test-done	1s
	1h 42m 23s

Provide feedback