httpstream: fix comparison for transfer-encoding

The http keyword was compared the wrong way around.
httpstream: reintroduce d318d544cf76ea58c4f12bccc0541d888af7570c:
	handle chunked transfers for statuscode 200

As suggested by malakudi, "transfer-encoding: chunked" is allowed for all
http status codes, not just 206. So check for chunked transfers on 200 as well.
Merge branch 'master' of git://git.code.sf.net/p/openpli/enigma2 into BETA