Due to a recent change in fm-api's directory structure, unit tests would
fail since the virtualenv would not be able to find fm-api/setup.py.
Adjust the tox.ini to point to the correct directory. Tested locally
by running tox.ini.
Depends-On: https://review.opendev.org/c/starlingx/fault/+/806046
Story: 2009101
Task: 43091
Signed-off-by: Charles Short <charles.short@windriver.com>
Change-Id: If55a6d92dc861b23516637fcb90c52852c3fd92a
b05192c800