logrotate: add ptest support

logrotate: add ptest support

Below is an extract of the test log:

root@qemux86-64:~# ptest-runner
START: ptest-runner
2023-04-05T12:20
BEGIN: /usr/lib/logrotate/ptest
make  check-TESTS
make[1]: Entering directory '/usr/lib/logrotate/ptest'
make[2]: Entering directory '/usr/lib/logrotate/ptest'
PASS: test-0001.sh
PASS: test-0002.sh
...
...
PASS: test-0107.sh
PASS: test-0108.sh
============================================================================
Testsuite summary for logrotate 3.21.0
============================================================================
 # TOTAL: 102
 # PASS:  97
 # SKIP:  5
 # XFAIL: 0
 # FAIL:  0
 # XPASS: 0
 # ERROR: 0
============================================================================
make[2]: Leaving directory '/usr/lib/logrotate/ptest'
make[1]: Leaving directory '/usr/lib/logrotate/ptest'
DURATION: 353
END: /usr/lib/logrotate/ptest
2023-04-05T12:26
STOP: ptest-runner
TOTAL: 1 FAIL: 0

Reviewed-by: Yoann CONGAL <yoann.congal@smile.fr>
Signed-off-by: Frank WOLFF <frank.wolff@smile.fr>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>