src/pkg/[a-m]*: gofix -r error -force=error

R=golang-dev, iant
CC=golang-dev
https://golang.org/cl/5322051
diff --git a/src/pkg/crypto/rand/rand_windows.go b/src/pkg/crypto/rand/rand_windows.go
index 0eab6b2..590571d 100644
--- a/src/pkg/crypto/rand/rand_windows.go
+++ b/src/pkg/crypto/rand/rand_windows.go
@@ -23,7 +23,7 @@
 	mu   sync.Mutex
 }
 
-func (r *rngReader) Read(b []byte) (n int, err os.Error) {
+func (r *rngReader) Read(b []byte) (n int, err error) {
 	r.mu.Lock()
 	if r.prov == 0 {
 		const provType = syscall.PROV_RSA_FULL