Merge pull request #39 from rhusar/MODCLUSTER-355

[MODCLUSTER-355] WFLY-1888 metric support for Undertow: allow busyness t...
Port MODCLUSTER-332 fix from 1.2.x branch.
Merge pull request #41 from pferraro/master

[master] Port MODCLUSTER-332 fix from 1.2.x branch.