use global handler for span export err in otlp (#946)

Currently there is no way to report errors using the global handlers for spans in the OTLP exporter, this change fixes that. Errors for the metrics exporter are already handled by the global handler.

Co-authored-by: Liz Fong-Jones <lizf@honeycomb.io>

exporters/otlp/otlp.go

@@ -28,6 +28,7 @@ import (
 	colmetricpb "go.opentelemetry.io/otel/internal/opentelemetry-proto-gen/collector/metrics/v1"
 	coltracepb "go.opentelemetry.io/otel/internal/opentelemetry-proto-gen/collector/trace/v1"
 
+	"go.opentelemetry.io/otel/api/global"
 	"go.opentelemetry.io/otel/api/metric"
 	"go.opentelemetry.io/otel/exporters/otlp/internal/transform"
 	metricsdk "go.opentelemetry.io/otel/sdk/export/metric"
@@ -301,6 +302,7 @@ func (e *Exporter) uploadTraces(ctx context.Context, sdl []*tracesdk.SpanData) {
 		e.senderMu.Unlock()
 		if err != nil {
 			e.setStateDisconnected(err)
+			global.Handle(err)
 		}
 	}
 }