use new time API

R=bradfitz, gri, r, dsymonds
CC=golang-dev
https://golang.org/cl/5390042
diff --git a/src/pkg/net/fd.go b/src/pkg/net/fd.go
index 70e04a2..5318c51 100644
--- a/src/pkg/net/fd.go
+++ b/src/pkg/net/fd.go
@@ -171,7 +171,7 @@
 }
 
 func (s *pollServer) Now() int64 {
-	return time.Nanoseconds()
+	return time.Now().UnixNano()
 }
 
 func (s *pollServer) CheckDeadlines() {