time: remove unused sysSleep

R=golang-dev, dsymonds, r
CC=golang-dev
https://golang.org/cl/5369094

src/pkg/time/sys_plan9.go

@@ -9,14 +9,6 @@ import (
 	"syscall"
 )
 
-func sysSleep(t int64) error {
-	err := syscall.Sleep(t)
-	if err != nil {
-		return os.NewSyscallError("sleep", err)
-	}
-	return nil
-}
-
 // for testing: whatever interrupts a sleep
 func interrupt() {
 	// cannot predict pid, don't want to kill group

src/pkg/time/sys_unix.go

@@ -11,14 +11,6 @@ import (
 	"syscall"
 )
 
-func sysSleep(t int64) error {
-	errno := syscall.Sleep(t)
-	if errno != 0 && errno != syscall.EINTR {
-		return os.NewSyscallError("sleep", errno)
-	}
-	return nil
-}
-
 // for testing: whatever interrupts a sleep
 func interrupt() {
 	syscall.Kill(os.Getpid(), syscall.SIGCHLD)

src/pkg/time/sys_windows.go

@@ -4,19 +4,6 @@
 
 package time
 
-import (
-	"os"
-	"syscall"
-)
-
-func sysSleep(t int64) error {
-	errno := syscall.Sleep(t)
-	if errno != 0 && errno != syscall.EINTR {
-		return os.NewSyscallError("sleep", errno)
-	}
-	return nil
-}
-
 // for testing: whatever interrupts a sleep
 func interrupt() {
 }