EXT-1643: Removed the FirstMedia first use popup.

The notification text for this popup is commented out of the
notifications.xml file, so I'm commenting out the code that tries to
pop up this notification too. This is just a quick short-term fix.  In
the longer term, I believe the plan is to remove all First Use dialogs
entirely, so this entire file will eventually die.

indra/newview/llfirstuse.cpp

@@ -272,6 +272,8 @@ void LLFirstUse::useMedia()
 	{
 		gWarningSettings.setBOOL("FirstMedia", FALSE);
 
-		LLNotifications::instance().add("FirstMedia");
+		// Popup removed as a short-term fix for EXT-1643.
+		// Ultimately, the plan is to kill all First Use dialogs
+		//LLNotifications::instance().add("FirstMedia");
 	}
 }