fix up use of createCodebasePrincipal to use origin attributes correctly

[dhuseby]

in the file browser/extensions/shumway/chrome/SpecialStorage.jsm line 27 there is a call to createCodebasePrincipal that doesn't handle origin attributes correctly:

var principal = ssm.createCodebasePrincipal(uri, {});

The solution is to query the document/docshell for the principal origin attributes and to either use the principal directly, or if a new principal must be created, passing in the origin attributes so that shumway properly isolates.