Rails includes a single character body to a head(:no_content) response to work around an old Safari bug where headers were ignored if no body sent.
This patch brings the behavior slightly closer to spec if :no_content/204 is explicity requested via a head only response.
Status comparison done on symbolic and numeric values
Not returning any content when responding with head and limited to a status code that explicitly states no content will be returned - 100..199, 204, 205, 304.
