This converts the usage of nsISupportsArray in nsIRDFDataSource to just
nsISupports. Internally none of the params are used, all external usages in
the addons repo appear to just be passthroughs.
Regardless, any external implementors wanting to pass in an nsISupportsArray
can still do so as it is derived from nsISupports.
Additionally the |IsCommandEnabled| and |DoCommand| stubs are updated to just
return NS_ERROR_NOT_IMPLEMENTED as this functionallity is currently not
supported.
MozReview-Commit-ID: JJSHAQKiLSZ
