Eliminate recursive MemberList locking in outbound::probe_mlr
Eliminate recursive MemberList locking in outbound::probe_mlr

In order to avoid the need to access the member list inside the
with_pingreq_targets_mlr, move the call to
populate_membership_rumors_mlr earlier. The most obvious potential risk
is if there is a significant write to the member list between the call
populate_membership_rumors_mlr and with_pingreq_targets_mlr, the
PingReq message could contain stale data, but that doesn't seem very
likely or of great concern.

Signed-off-by: Jon Bauman <e6c6a4db54ad11b4de69fed67139594b59f3444f@users.noreply.github.com>

rsertelon/habitat,rsertelon/habitat,habitat-sh/habitat,habitat-sh/habitat,habitat-sh/habitat,rsertelon/habitat,rsertelon/habitat,habitat-sh/habitat,rsertelon/habitat,habitat-sh/habitat,rsertelon/habitat,habitat-sh/habitat,habitat-sh/habitat,habitat-sh/habitat,rsertelon/habitat