Fix breakage introduced by r6691.

ModuleRtpRtcpImpl returned incorrectly on RemoteNTP as the
RTCPReceiver::NTP changed return type.

BUG=
TBR=stefan@webrtc.org

Review URL: https://webrtc-codereview.appspot.com/18799004

git-svn-id: http://webrtc.googlecode.com/svn/trunk/webrtc@6693 4adac7df-926f-26a2-2b94-8c16560cd09d
diff --git a/modules/rtp_rtcp/source/rtp_rtcp_impl.cc b/modules/rtp_rtcp/source/rtp_rtcp_impl.cc
index 1fb0c5d..a26b36a 100644
--- a/modules/rtp_rtcp/source/rtp_rtcp_impl.cc
+++ b/modules/rtp_rtcp/source/rtp_rtcp_impl.cc
@@ -765,7 +765,9 @@
                             received_ntpfrac,
                             rtcp_arrival_time_secs,
                             rtcp_arrival_time_frac,
-                            rtcp_timestamp);
+                            rtcp_timestamp)
+             ? 0
+             : -1;
 }
 
 // Get RoundTripTime.