Remove TODOs from metrics.proto. Remaining todos are bugs against spe…

…cification/proto library. (#293)

opentelemetry/proto/metrics/v1/metrics.proto

@@ -114,11 +114,6 @@ message Metric {
   // described by http://unitsofmeasure.org/ucum.html.
   string unit = 3;
 
-  // TODO: Decide if support for RawMeasurements (measurements recorded using
-  // the synchronous instruments) is necessary. It can be used to delegate the
-  // aggregation from the application to the agent/collector. See
-  // https://github.com/open-telemetry/opentelemetry-specification/issues/617
-
   // Data determines the aggregation type (if any) of the metric, what is the
   // reported value type for the data points, as well as the relatationship to
   // the time interval over which they are reported.