…mgr::doTask

The switch statement which would normally erase buffer events was moved
to be inside the if-statement which would only enter if the event is a
SET event. This was introduced in commit e5329c39.

This would cause an infinite loop, since non-set events would never be
erased.

The switch statement has now been moved to occur outside the if,
allowing for non-set commands to be processed.

Signed-off-by: mazora <mazora@marvell.com>

Adding test to increase code coverage. Since this test is a
"negative" test, meaning that it should not be a valid configurations,
I only validate if the test succeeds based off of syslogs.

Added imports for type hinting.

Getting value by indexing could cause KeyError if value
does not exist, instead call get() function which will return
None if value does not exist.

Also moved add_log_marker() function earlier to not accidently miss
the syslog.

check_syslog() did not have "self" param

call to check_syslog did not send dvs arg