Remove some leftover threadpool cruft.
Remove some leftover threadpool cruft.

Change-Id: I43a1a428bd96a2e18aac334c03743a9f94f7d3e1

openstack/swift,matthewoliver/swift,matthewoliver/swift,nadeemsyed/swift,tipabu/swift,matthewoliver/swift,tipabu/swift,smerritt/swift,nadeemsyed/swift,openstack/swift,openstack/swift,nadeemsyed/swift,smerritt/swift,matthewoliver/swift,swiftstack/swift,swiftstack/swift,smerritt/swift,tipabu/swift,openstack/swift,smerritt/swift,tipabu/swift,nadeemsyed/swift,swiftstack/swift