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

@@ -259,28 +259,27 @@ func (p *ConnPool) getNewConn(addr net.Addr, version int) (*Conn, error) {
 	}
 
 	// Wrap the connection
-	var c *Conn
+	c := &Conn{
+		refCount: 1,
+		addr:     addr,
+		session:  session,
+		clients:  list.New(),
+		lastUsed: time.Now(),
+		version:  version,
+		pool:     p,
+	}
 
 	// Track this connection, handle potential race condition
 	p.Lock()
-	defer p.Unlock()
-
 	if existing := p.pool[addr.String()]; existing != nil {
-		c = existing
+		c.Close()
+		p.Unlock()
+		return existing, nil
 	} else {
-		c = &Conn{
-			refCount: 1,
-			addr:     addr,
-			session:  session,
-			clients:  list.New(),
-			lastUsed: time.Now(),
-			version:  version,
-			pool:     p,
-		}
 		p.pool[addr.String()] = c
+		p.Unlock()
+		return c, nil
 	}
-
-	return c, nil
 }
 
 // clearConn is used to clear any cached connection, potentially in response to an erro