ob_gzhandler() crash fix when browser e.g. does not send "accept-encoding" header properly
ob_gzhandler() crash fix when browser e.g. does not send "accept-encoding" header properly

git-tfs-id: [http://falcon:8080/tfs/Projects]$/Phalanger/Main;C2139

kendallb/Phalanger,DEVSENSE/Phalanger,kendallb/Phalanger,diddledan/Phalanger,DEVSENSE/Phalanger,kendallb/Phalanger,DEVSENSE/Phalanger,DEVSENSE/Phalanger,diddledan/Phalanger,diddledan/Phalanger,diddledan/Phalanger,DEVSENSE/Phalanger,kendallb/Phalanger,kendallb/Phalanger,diddledan/Phalanger,kendallb/Phalanger,DEVSENSE/Phalanger