Fix redirects

[ShoshinNikita]

Before this change redirects didn't work because method Service.extendMapper didn't copy the value of URLMapper.RedirectType to the extended result.

To fix this we return the original URLMapper instead of creating a new one (it can also help to avoid similar bugs in the future). We can reuse URLMapper because it is passed by value.

[ShoshinNikita]

2022/11/07 13:47:25 INFO  activate http proxy server on 127.0.0.1:49700
    proxy_test.go:66: 
            Error Trace:    proxy_test.go:66
            Error:          Received unexpected error:
                            Get "http://127.0.0.1:49700/api/something": dial tcp 127.0.0.1:49700: connect: connection refused
            Test:           TestHttp_Do
--- FAIL: TestHttp_Do (0.06s)

I reproduced this fail (~1/50 test runs). It looks like the 10ms delay (app/proxy/proxy_test.go:58) sometimes is not long enough. I can increase it to 20ms, for example. Another option is to just re-run CI.

[ShoshinNikita]

2022/11/07 14:06:38.404 [INFO]  {logger/logger.go:134 logger.(*Middleware).Handler.func1.1} GET - /svc2/test - 127.0.0.1 - 127.0.0.1 - 404 (43) - 169.961115ms
main_test.go:81: 
      Error Trace:  main_test.go:81
      Error:        Not equal: 
                    expected: 200
                    actual  : 404
      Test:         Test_Main
main_test.go:84: 
      Error Trace:  main_test.go:84
      Error:        "404 page not found\n" does not contain "echo echo 123"
      Test:         Test_Main

app/main_test.go:28

"--static.rule=*,/svc2/(.*), https://echo.umputun.com/$1,https://feedmaster.umputun.com/ping",

It looks like https://echo.umputun.com/test doesn't work as expected anymore. I am not sure what caused this. Should I update expected status code and body?

[umputun]

It looks like https://echo.umputun.com/test doesn't work as expected anymore

should be back

[ShoshinNikita]

I think the decrease of coverage by 0.02% is not very critical. Especially, I believe it is caused by code removal.