unit-test.py: Remove objmgr workaround
unit-test.py: Remove objmgr workaround

As was done in build-unit-test-docker.sh, this commit removes
a phosphor-objmgr workaround that was needed due to a systemd
dependency that doesn't exist anymore.

Tested: Ran run-unit-test-docker.sh.

Change-Id: Ica85023330a4e102f0ecc7e8b7b1c8bb411fb1e8
Signed-off-by: Matt Spinler <c000c989d08c98662d98f15448f11de169feb92d@us.ibm.com>

openbmc/openbmc-build-scripts,openbmc/openbmc-build-scripts