os: fix comment per CL 5370091

Made the edit in the wrong client before submitting.

TBR=r
CC=golang-dev
https://golang.org/cl/5374091

src/pkg/os/proc.go

@@ -8,7 +8,7 @@ package os
 
 import "syscall"
 
-// Args is the command-line arguments, starting with the program name.
+// Args hold the command-line arguments, starting with the program name.
 var Args []string
 
 // Getuid returns the numeric user id of the caller.