Fix creating a backup of htp config.  This is used by unittests that
changed htp config.
Introduce a saner way to validate the completion of request and
response bodies.

Also don't change app state for http from inside inspection.
unittests for gzip, deflate http compression, multiple stacked
compressions, cunning compression that's not what it says it is, etc.

These unittests are tweaked to pass.  When libhtp fixes these issues
we will have to reenable them.