optimized the buffer management process a bit for ngx.location.capture*: one the response body is a single buf chain, do not bother concatening it into a new buffer.
optimized the buffer management process a bit for ngx.location.capture*: one the response body is a single buf chain, do not bother concatening it into a new buffer.

yeahdongcn/SEnginx,yeahdongcn/SEnginx,yeahdongcn/SEnginx,yeahdongcn/SEnginx,yeahdongcn/SEnginx,yeahdongcn/SEnginx,yeahdongcn/SEnginx