VOL-3588 Update OFAgent to support new version of protos

Change-Id: Ic3944779f9a600ebcd5d7a916616f473059e311e
diff --git a/vendor/github.com/opentracing/opentracing-go/log/field.go b/vendor/github.com/opentracing/opentracing-go/log/field.go
index 50feea3..f222ded 100644
--- a/vendor/github.com/opentracing/opentracing-go/log/field.go
+++ b/vendor/github.com/opentracing/opentracing-go/log/field.go
@@ -122,16 +122,19 @@
 	}
 }
 
-// Error adds an error with the key "error" to a Span.LogFields() record
+// Error adds an error with the key "error.object" to a Span.LogFields() record
 func Error(err error) Field {
 	return Field{
-		key:          "error",
+		key:          "error.object",
 		fieldType:    errorType,
 		interfaceVal: err,
 	}
 }
 
 // Object adds an object-valued key:value pair to a Span.LogFields() record
+// Please pass in an immutable object, otherwise there may be concurrency issues.
+// Such as passing in the map, log.Object may result in "fatal error: concurrent map iteration and map write".
+// Because span is sent asynchronously, it is possible that this map will also be modified.
 func Object(key string, obj interface{}) Field {
 	return Field{
 		key:          key,
@@ -140,6 +143,16 @@
 	}
 }
 
+// Event creates a string-valued Field for span logs with key="event" and value=val.
+func Event(val string) Field {
+	return String("event", val)
+}
+
+// Message creates a string-valued Field for span logs with key="message" and value=val.
+func Message(val string) Field {
+	return String("message", val)
+}
+
 // LazyLogger allows for user-defined, late-bound logging of arbitrary data
 type LazyLogger func(fv Encoder)
 
diff --git a/vendor/github.com/opentracing/opentracing-go/log/util.go b/vendor/github.com/opentracing/opentracing-go/log/util.go
index 3832feb..d57e28a 100644
--- a/vendor/github.com/opentracing/opentracing-go/log/util.go
+++ b/vendor/github.com/opentracing/opentracing-go/log/util.go
@@ -1,6 +1,9 @@
 package log
 
-import "fmt"
+import (
+	"fmt"
+	"reflect"
+)
 
 // InterleavedKVToFields converts keyValues a la Span.LogKV() to a Field slice
 // a la Span.LogFields().
@@ -46,6 +49,10 @@
 		case float64:
 			fields[i] = Float64(key, typedVal)
 		default:
+			if typedVal == nil || (reflect.ValueOf(typedVal).Kind() == reflect.Ptr && reflect.ValueOf(typedVal).IsNil()) {
+				fields[i] = String(key, "nil")
+				continue
+			}
 			// When in doubt, coerce to a string
 			fields[i] = String(key, fmt.Sprint(typedVal))
 		}