net: remove types InvalidConnError and UnknownSocketError

Both are unused and undocumented.

InvalidConnError is also non-idiomatic: a FooError type can
typically describe something, else it would be an ErrFoo
variable.

R=golang-dev, alex.brainman
CC=golang-dev
https://golang.org/cl/5609045

src/pkg/net/fd.go

@@ -43,12 +43,6 @@ type netFD struct {
 	ncr, ncw int
 }
 
-type InvalidConnError struct{}
-
-func (e *InvalidConnError) Error() string   { return "invalid Conn" }
-func (e *InvalidConnError) Temporary() bool { return false }
-func (e *InvalidConnError) Timeout() bool   { return false }
-
 // A pollServer helps FDs determine when to retry a non-blocking
 // read or write after they get EAGAIN.  When an FD needs to wait,
 // send the fd on s.cr (for a read) or s.cw (for a write) to pass the

src/pkg/net/fd_windows.go

@@ -14,12 +14,6 @@ import (
 	"unsafe"
 )
 
-type InvalidConnError struct{}
-
-func (e *InvalidConnError) Error() string   { return "invalid Conn" }
-func (e *InvalidConnError) Temporary() bool { return false }
-func (e *InvalidConnError) Timeout() bool   { return false }
-
 var initErr error
 
 func init() {

src/pkg/net/sock.go

@@ -10,7 +10,6 @@ package net
 
 import (
 	"io"
-	"reflect"
 	"syscall"
 )
 
@@ -70,14 +69,6 @@ func socket(net string, f, t, p int, la, ra syscall.Sockaddr, toAddr func(syscal
 	return fd, nil
 }
 
-type UnknownSocketError struct {
-	sa syscall.Sockaddr
-}
-
-func (e *UnknownSocketError) Error() string {
-	return "unknown socket address type " + reflect.TypeOf(e.sa).String()
-}
-
 type writerOnly struct {
 	io.Writer
 }