Cleanup event queue before monotonic time change

Since we want to convert the event queue to monotonic time, we need to
clean it up first.

Signed-off-by: Max Sikstrom <msikstrom@op5.com>
NULL-terminate readed data in log tests

Not all systems zero out their memory from the beginning, so add a null
byte at the end, so we don't read to long.

read() is a binary read, and returns the length, but doesn't
null-byte-terminate

Signed-off-by: Max Sikstrom <msikstrom@op5.com>