http: Fix parse long headers names

Bug: During parsing http headers, long headers names are truncated
to zero length, but values are not ignored.

Fix this with adding parameter  max_header_name_length to http request.
If header name is bigger than this value, header name is truncated to
this length. Default value of max_header_name_length is 32.

Do some refactoring with renaming long names in http_parser.

Closes #3451