fix: error was passed in duplicate

src/index.js

@@ -38,11 +38,6 @@ function TCP () {
       conn.emit('timeout')
     })
 
-    socket.on('error', (err) => {
-      callback(err)
-      conn.emit('error', err)
-    })
-
     socket.on('connect', () => {
       callback(null, conn)
       conn.emit('connect')

test/libp2p-tcp.spec.js

@@ -214,6 +214,15 @@ describe('dial', () => {
     conn.on('end', done)
   })
 
+  it('dial to non existent listener', (done) => {
+    const ma = multiaddr('/ip4/127.0.0.1/tcp/8989')
+    const conn = tcp.dial(ma)
+    conn.on('error', (err) => {
+      expect(err).to.exist
+      done()
+    })
+  })
+
   it('dial on IPv6', (done) => {
     const ma = multiaddr('/ip6/::/tcp/9066')
     const listener = tcp.createListener((conn) => {