don't copy lock

govet pointed out that I was copying a lock when creating/assigning the
connection object. It didn't cause any issues, but was a bad practice.
diff --git a/request-server.go b/request-server.go
index 4d9be45..7a94801 100644
--- a/request-server.go
+++ b/request-server.go
@@ -26,7 +26,7 @@
 
 // RequestServer abstracts the sftp protocol with an http request-like protocol
 type RequestServer struct {
-	serverConn
+	*serverConn
 	Handlers        Handlers
 	pktMgr          packetManager
 	openRequests    map[string]Request
@@ -37,7 +37,7 @@
 // NewRequestServer creates/allocates/returns new RequestServer.
 // Normally there there will be one server per user-session.
 func NewRequestServer(rwc io.ReadWriteCloser, h Handlers) *RequestServer {
-	svrConn := serverConn{
+	svrConn := &serverConn{
 		conn: conn{
 			Reader:      rwc,
 			WriteCloser: rwc,
@@ -46,7 +46,7 @@
 	return &RequestServer{
 		serverConn:   svrConn,
 		Handlers:     h,
-		pktMgr:       newPktMgr(&svrConn),
+		pktMgr:       newPktMgr(svrConn),
 		openRequests: make(map[string]Request),
 	}
 }
diff --git a/server.go b/server.go
index 2bc1561..db3270a 100644
--- a/server.go
+++ b/server.go
@@ -26,7 +26,7 @@
 // This implementation currently supports most of sftp server protocol version 3,
 // as specified at http://tools.ietf.org/html/draft-ietf-secsh-filexfer-02
 type Server struct {
-	serverConn
+	*serverConn
 	debugStream   io.Writer
 	readOnly      bool
 	pktMgr        packetManager
@@ -75,7 +75,7 @@
 //
 // A subsequent call to Serve() is required to begin serving files over SFTP.
 func NewServer(rwc io.ReadWriteCloser, options ...ServerOption) (*Server, error) {
-	svrConn := serverConn{
+	svrConn := &serverConn{
 		conn: conn{
 			Reader:      rwc,
 			WriteCloser: rwc,
@@ -84,7 +84,7 @@
 	s := &Server{
 		serverConn:  svrConn,
 		debugStream: ioutil.Discard,
-		pktMgr:      newPktMgr(&svrConn),
+		pktMgr:      newPktMgr(svrConn),
 		openFiles:   make(map[string]*os.File),
 		maxTxPacket: 1 << 15,
 	}