Revert change to run unix socket channel tests on 5.0
Revert change to run unix socket channel tests on 5.0

A few tests that only run on 4.4+ fail when using unix socket channels.
Until we figure out why, continue running them on 4.2 instead.

rozza/mongo-java-driver,jyemin/mongo-java-driver,jyemin/mongo-java-driver,rozza/mongo-java-driver