Commit 4 on 6 to fix reentrance (incomplete Zlib header or validation bytes)...

Commit 4 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 non blocking reads which would block in the inflate input filter (not an error).


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@1572669 13f79535-47bb-0310-9956-ffa450edef68