QtNetwork: handle raw deflate compressed data in Http.

QtNetwork: handle raw deflate compressed data in Http.

For raw deflate compressed data with no zlib or gzip header
we need to call initInflate2 with -MAX_WBITS.

The first call to inflate will asume that the data has a header,
but if that call fails with a Z_DATA_ERROR we can try once more
with changed windowBits incase the data was raw compressed data
without a header.

Task-number: QTBUG-25513
Change-Id: Ib37c286c6da6d5395581717d0e76a0dbd5df289c
Reviewed-by: Shane Kearns <shane.kearns@accenture.com>