Get rid of dead Makefile targets
Get rid of dead Makefile targets

There are no longer any tests left over that can be run on tox. All tests are
run as D-Bus tests. Remove similar coverage target.

Signed-off-by: mulhern <7b51bcf507bcd7afb72bf8663752c0ddbeb517f6@redhat.com>

stratis-storage/stratis-cli,stratis-storage/stratis-cli