use dep as denpendency managment tool

vendor/github.com/docker/go-connections/sockets/inmem_socket_test.go

@@ -1,39 +0,0 @@
-package sockets
-
-import "testing"
-
-func TestInmemSocket(t *testing.T) {
-	l := NewInmemSocket("test", 0)
-	defer l.Close()
-	go func() {
-		for {
-			conn, err := l.Accept()
-			if err != nil {
-				return
-			}
-			conn.Write([]byte("hello"))
-			conn.Close()
-		}
-	}()
-
-	conn, err := l.Dial("test", "test")
-	if err != nil {
-		t.Fatal(err)
-	}
-
-	buf := make([]byte, 5)
-	_, err = conn.Read(buf)
-	if err != nil {
-		t.Fatal(err)
-	}
-
-	if string(buf) != "hello" {
-		t.Fatalf("expected `hello`, got %s", string(buf))
-	}
-
-	l.Close()
-	conn, err = l.Dial("test", "test")
-	if err != errClosed {
-		t.Fatalf("expected `errClosed` error, got %v", err)
-	}
-}