Refresh feature-commit-cb to handle new context

diff --cc zfs/lib/libzpool/dmu_tx.c
Simple merge

diff --cc zfs/lib/libzpool/include/sys/dmu.h
Simple merge

diff --cc zfs/lib/libzpool/include/sys/dmu_impl.h
Simple merge

diff --cc zfs/lib/libzpool/include/sys/dmu_tx.h
Simple merge

diff --cc zfs/lib/libzpool/include/sys/txg.h
Simple merge

diff --cc zfs/lib/libzpool/include/sys/txg_impl.h
Simple merge

diff --cc zfs/lib/libzpool/txg.c
Simple merge