function onRead( error, results ) {
		if ( error ) {
			debug( 'Encountered an error while attempting to read installed packages: %s.', error.message );
			return done( error );
		}
		debug( 'Successfully read installed packages.' );
		results = recurse( {}, results );
		done( null, toArray( results ) );
	}
Callback invoked after reading installed packages.

@private
@param {(Error|null)} error - error object
@param {Object} results - results
@returns {void}