httpproxy: fix capnslog log path

We changed the package path, so log paths needs to be updated as well.

proxy/httpproxy/reverse.go

@@ -34,7 +34,7 @@ import (
 )
 
 var (
-	plog = capnslog.NewPackageLogger("github.com/coreos/etcd", "proxy")
+	plog = capnslog.NewPackageLogger("github.com/coreos/etcd/proxy", "httpproxy")
 
 	// Hop-by-hop headers. These are removed when sent to the backend.
 	// http://www.w3.org/Protocols/rfc2616/rfc2616-sec13.html