High: PE: Apply (failure-)stickiness values to the whole group, not the individual resources
This allows for much simpler calculation of when groups migrate.
N ::= Number of resources in the group
M ::= Combined number of failures by any member of the group
Assuming no rsc_location constraints, the group will migrate when (N * stickiness) < (M * failure_stickiness)

Mercurial revision: e27628f78692f7d677affb988eeb0c66e904b39e