src/pkg/[n-z]*: gofix -r error -force=error

R=golang-dev, bsiegert, iant
CC=golang-dev
https://golang.org/cl/5294074
diff --git a/src/pkg/reflect/value.go b/src/pkg/reflect/value.go
index 9ddbee0..a9a7e09 100644
--- a/src/pkg/reflect/value.go
+++ b/src/pkg/reflect/value.go
@@ -71,7 +71,7 @@
 	Kind   Kind
 }
 
-func (e *ValueError) String() string {
+func (e *ValueError) Error() string {
 	if e.Kind == 0 {
 		return "reflect: call of " + e.Method + " on zero Value"
 	}