uhd: log timestamp on receive error

Currently, upon receiving an unexpected timestamp, the sample
buffer will error and log its internal state. The errant
timestamp is not logged though. This patch fixes that.

Signed-off-by: Thomas Tsou <ttsou@vt.edu>

public-trunk/Transceiver/UHDDevice.cpp

@@ -494,6 +494,9 @@ std::string UHDDevice::stringCode(uhd::rx_metadata_t metadata)
 		ost << "Unknown error " << metadata.error_code;
 	}
 
+	if (metadata.has_time_spec)
+		ost << " at " << metadata.time_spec.get_real_secs() << " sec.";
+
 	return ost.str();
 }