Adds options to mark when a file is final.

Adds options to mark when a file is final.

This takes the form of an option to add the pid of the process to file
names. Additionally, it adds a suffix to the file name to indicate it is
not finalized.

Adding the pid to the file name reduces the likelihood that a file is
overwritten when suricata is unexpectedly killed. The number in the
waldo file is only written out during a clean shutdown. In the event
of an improper shutdown, extracted files will be written using the old
number and existing files with the same name will be overwritten.

Writes extracted files and their metadata to a temporary file suffixed
with '.tmp'. Renames the files when they are completely done being
written. As-is there is no way to know that a file on disk is still
being written to by suricata.