selftest: Specifically remove files generated by provision

This allows the changes in 74d15c9b to
be reverted, and aligns this test with others that use TestCaseInTempDir.

BUG: https://bugzilla.samba.org/show_bug.cgi?id=13978

Signed-off-by: Andrew Bartlett <abartlet@samba.org>
Reviewed-by: Douglas Bagnall <douglas.bagnall@catalyst.net.nz>
(backported by abartlet@samba.org from commit ab376a97)

Signed-off-by: Andrew Bartlett <abartlet@samba.org>
15 jobs for abartlet-v4-9-downgradedatabase in 198 minutes and 47 seconds (queued for 2 seconds)
Status Job ID Name Coverage
  Build
passed #228158758
shared docker
build_ctdb

00:18:07

passed #228158760
shared docker
build_others

00:14:50

passed #228158761
private docker
build_samba

03:18:44

passed #228158765
private docker
build_samba_ad_dc

01:04:05

passed #228158755
shared docker
build_samba_ad_dc_2

00:27:20

passed #228158759
shared docker
build_samba_ctdb

00:41:23

passed #228158764
private docker
build_samba_fileserver

00:17:05

passed #228158756
shared docker
build_samba_libs

00:20:23

passed #228158750
shared docker
build_samba_none_env

00:47:57

passed #228158751
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build_samba_nopython

00:25:05

passed #228158763
private docker
build_samba_nt4

00:32:32

passed #228158754
shared docker
build_samba_o3

00:18:40

passed #228158757
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build_samba_static

00:49:10

passed #228158752
shared docker
build_samba_systemkrb5

00:16:08

passed #228158753
shared docker
build_samba_xc

00:07:12