Fixed missing find_if namespace qualification.
Fixed missing find_if namespace qualification.

See 0273fbc2638c581528cc5819da2e0c9b1a9c235e for why this is needed.
This one was just left out from that commit, but is included in
FreeBSD's patches.

This closes #357

dforsyth/mesos,dforsyth/mesos,reneploetz/mesos,reneploetz/mesos,abudnik/mesos,Gilbert88/mesos,dforsyth/mesos,Gilbert88/mesos,Gilbert88/mesos,abudnik/mesos,abudnik/mesos,reneploetz/mesos,dforsyth/mesos,abudnik/mesos,Gilbert88/mesos,Gilbert88/mesos,reneploetz/mesos,Gilbert88/mesos,dforsyth/mesos,reneploetz/mesos,dforsyth/mesos,abudnik/mesos,reneploetz/mesos,abudnik/mesos,dforsyth/mesos,Gilbert88/mesos,reneploetz/mesos,abudnik/mesos