Commit 3 on 6 to fix reentrance (incomplete Zlib header or validation bytes)...

Commit 3 on 6 to fix reentrance (incomplete Zlib header or validation bytes) in mod_deflate's output and input filters.
PR 46146 (patches from duplicated PR 55666)

Handle Zlib validation bytes buffering (CRC + length) in the inflate input filter :
- use validation_buffer and validation_length as state,
- loop until all the bytes are received.


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@1572668 13f79535-47bb-0310-9956-ffa450edef68