Enable F841 flake8 check 'variables assigned but unused'.
This primarily involved removing the variable or renaming
it as '_' to indicate it is an unused variable.
There should be no runtime difference from these changes.
Test Plan:
PASS: tox
PASS: sw-manager strategy creation (CLI commands)
Story: 2010531
Task: 47606
Signed-off-by: Al Bailey <al.bailey@windriver.com>
Change-Id: I2431fe0c0ec7d6e01ab72668efc20c9c5e77e88f
6f68610806