virsh: Fix comment of vshCmdInfo

The original comment of vshCmdInfo:
"name" - command name

Actually it's 'help' and the short description
of command, not the command name.
Signed-off-by: NLi Yang <liyang.fnst@cn.fujitsu.com>

tools/virsh.h

@@ -154,7 +154,7 @@ typedef char **(*vshCompleter)(unsigned int flags);
  * vshCmdInfo -- name/value pair for information about command
  *
  * Commands should have at least the following names:
- * "name" - command name
+ * "help" - short description of command
  * "desc" - description of command, or empty string
  */
 struct _vshCmdInfo {