qa/cephadm: ignore stray daemon warning during rados_api_tests
The "stray daemon" that is getting logged about in this test is
from "stray daemon laundry.pid70383 on host smithi027 not managed by cephadm".
It seems the rados_api_tests is creating some additional "laundry" entity
during these tests that gets reported as an actual daemon in the mgr,
but cephadm is unaware of it, resulting in the warning. Originally
we thought to maybe add "laundry" itself to the ignorelist, but
without an additional patch that added extra logging for debug
purposes (which can't be merged) the log statement found in
the logs due to this problem will not say what daemon it found
to be stray. There will just be a generic warning about a stray
daemon. In a real cluster, a user would then check "ceph health detail"
to find out what daemon is stray, but the log scraper can't do this
and just fails the test due to the presence of the warning.