interfaces: drop the `raw` parameters on ifiledata interface
In practice it was not implemented since forever. The `rawdata` method fit that
purpose. The interface checking does not detect that because it seems to confuse
the `_df` argument for the `raw` one.
Dropping that `_df` argument in a descendant changesets revealed the issue.
{
// Enforcing
"eqeqeq" : true, // true: Require triple equals (===) for comparison
"forin" : true, // true: Require filtering for..in loops with obj.hasOwnProperty()
"freeze" : true, // true: prohibits overwriting prototypes of native objects such as Array, Date etc.
"nonbsp" : true, // true: Prohibit "non-breaking whitespace" characters.
"undef" : true, // true: Require all non-global variables to be declared (prevents global leaks)
// Environments
"browser" : true // Web Browser (window, document, etc)
}