Merge request for the topic/seth/deflate-missing-headers-fix branch.
It fixes an issue that is occasionally but regularly seen where servers don't include the headers correctly for deflated content. Browsers cope with this situation just fine and this change makes Bro also deal with the situation.
Could we postpone this to 2.5? It's a nontrivial code change, and not a regression. Messing with that code during the beta worries me a bit.
Setting version so that we will discuss.