net: move testHookSetKeepAlive into hook.go

Change-Id: I1f2d4e3b0351a7a47c3a6073833a17dbc0c7b05c
Reviewed-on: https://go-review.googlesource.com/8520Reviewed-by: Ian Lance Taylor <iant@golang.org>

src/net/dial.go

@@ -180,8 +180,6 @@ func (d *Dialer) Dial(network, address string) (Conn, error) {
 	return c, err
 }
 
-var testHookSetKeepAlive = func() {} // changed by dial_test.go
-
 // dialMulti attempts to establish connections to each destination of
 // the list of addresses. It will return the first established
 // connection and close the other connections. Otherwise it returns

src/net/hook.go

@@ -4,4 +4,7 @@
 
 package net
 
-var testHookLookupIP = func(fn func(string) ([]IPAddr, error), host string) ([]IPAddr, error) { return fn(host) }
+var (
+	testHookLookupIP     = func(fn func(string) ([]IPAddr, error), host string) ([]IPAddr, error) { return fn(host) }
+	testHookSetKeepAlive = func() {}
+)