base fetch: populate the response status code
base fetch: populate the response status code

Copy the response status code from nginx to pagespeed.

Merge of Otto's pull request #60

wanrui/ngx_pagespeed,digideskio/ngx_pagespeed,pagespeed/ngx_pagespeed,pagespeed/ngx_pagespeed,wanrui/ngx_pagespeed,0x0mar/ngx_pagespeed,0x0mar/ngx_pagespeed,digideskio/ngx_pagespeed