http: fix "Expect: 100-continue" client side Instead of sending data always at the beginning of the request wait until the server will respond with "HTTP/1.1 100 Continue". Before this patch server do send "HTTP/1.1 100 Continue" but client always send post data even without waiting server response. P.S. this patch also touches some not 100% related tab-align issues. Covered-by: http/data_length_constraints Covered-by: http/read_on_write_error