Revert "* use defer to avoid tracking lock"

This reverts commit a030abdefc54470394a2a44008e02f3b3d0510ec.
This commit causes a connection to be leaked if there is a race with
another concurrent RPC.

consul/pool.go

@@ -259,16 +259,7 @@ func (p *ConnPool) getNewConn(addr net.Addr, version int) (*Conn, error) {
 	}
 
 	// Wrap the connection
-	var c *Conn
-
-	// Track this connection, handle potential race condition
-	p.Lock()
-	defer p.Unlock()
-
-	if existing := p.pool[addr.String()]; existing != nil {
-		c = existing
-	} else {
-		c = &Conn{
+	c := &Conn{
 		refCount: 1,
 		addr:     addr,
 		session:  session,
@@ -277,11 +268,19 @@ func (p *ConnPool) getNewConn(addr net.Addr, version int) (*Conn, error) {
 		version:  version,
 		pool:     p,
 	}
-		p.pool[addr.String()] = c
-	}
 
+	// Track this connection, handle potential race condition
+	p.Lock()
+	if existing := p.pool[addr.String()]; existing != nil {
+		c.Close()
+		p.Unlock()
+		return existing, nil
+	} else {
+		p.pool[addr.String()] = c
+		p.Unlock()
 		return c, nil
 	}
+}
 
 // clearConn is used to clear any cached connection, potentially in response to an erro
 func (p *ConnPool) clearConn(conn *Conn) {