merge topic/jsiwek/improve-input-reread

Attempting to address a (rare) unit test failure, https://travis-ci.org/bro/bro/jobs/417466827, this branch in the bro repo changes some input framework tests to use atomic 'mv' operations instead of 'cp', which is the most plausible way I can think for that failure to have happened. Also made the input framework recognize different inode number or different (opposed to just newer) modifications times as meaning the file changed.