Title: #956: tests: fix race confition in enumeration tests
The problem with these tests is that ldap_conn has scope=module and the fixture that fills
the ldap contents before the test has scope=function (default), so there can be leftovers
from previous test run in the passwd result (enumeration) after the fixture with function
scope was executed, but the enumeration results are still cached in SSSD. I really do not
know why we decided to go with INTERACTIVE_TIMEOUT/2 and I wonder if it was supposed to be
INTERACTIVE_TIMEOUT*2 instead, which would make much more sense to me. However
INTERACTIVE_TIMEOUT is probably ok as well, unless something slows SSSD really a lot. Now,
of course we can speculate what number would be actually good... if this function fails in
the future again, we can change it to INTERACTIVE_TIMEOUT * 2, but again, I do not have
good explanation or justification other then "maybe sometimes SSSD will need more
time for the cached enumeration result to actualy time out, despite the timeout being
INTERACTIVE_TIMEOUT in the sssd.conf".
Also the way we picked the INTERACTIVE_TIMEOUT was kind of "this seems to work"
method. IIRC in the first version it was 2, but that turned out to not be enough in some
cases and caused the tests to fail "sometimes".
See the full comment at https://github.com/SSSD/sssd/pull/956#issuecomment-562197555