validator flags "cache-control" for html5

*Errror:
Line 7, Column 52*: Bad value cache-control for attribute http-equiv on
element meta.

<meta http-equiv="cache-control" content="no-cache"*/>

However, this is exactly the example given at
http://www.w3schools.com/html5/att_meta_http-equiv.asp

futhermore, this only fails for HTML5, and I think that it is incorrect.
*