Merge of r3964, r3977, r3978: Proxy related fixes: *) finalizing with rc == 0 in unbuffered proxy mode caused nginx to wait for another send_timeout before actually closing client's connection if client timed out while still talking to upstream server *) update r3945 with more descriptive error message *) test length of proxy_pass with variables; patch by Lanshun Zhou

# Copyright (C) Igor Sysoev


have=NGX_SUPPRESS_WARN . auto/have

have=NGX_SMP . auto/have