Fix http headers parsing + Remove unused code + Fix indentation

Summary: This PR does three things:

 - Remove an unused variable in the http-client
 - Fix indentation of one of my previous commit
 - Fix the http headers parsing (Fixes #3241)

Regarding the fix about the http header parsing, the [RFC-2616](http://tools.ietf.org/html/rfc2616#section-4.2) specifies that the field value **MAY** be preceded by any amount of LWS, though a single SP is preferred. So, an header value not preceded by a space is valid.

Closes https://github.com/facebook/hhvm/pull/3248

Reviewed By: @JoelMarcey

Differential Revision: D1447936

Pulled By: svcscm