Fix disabling anisotropic filtering.

The anisotropic value needs to be set to 1 to disable it, not 0.
Anti-aliasing also had the same logic, so I updated that as well.
Technically that disabled with either 0 or 1, but the BZDB value for
multisample was 1 for disabled.

src/bzflag/DisplayMenu.cxx

@@ -471,7 +471,7 @@ void            DisplayMenu::callback(HUDuiControl* w, const void* data)
     case 'A':
     {
         int aniso = list->getIndex();
-        BZDB.setInt("aniso", (aniso == 0)?0:(int)pow(2, aniso));
+        BZDB.setInt("aniso", (int)pow(2, aniso));
         TextureManager& tm = TextureManager::instance();
         tm.setMaxFilter(tm.getMaxFilter());
         sceneRenderer->notifyStyleChange();
@@ -517,7 +517,7 @@ void            DisplayMenu::callback(HUDuiControl* w, const void* data)
     case 'm':
     {
         int multi = list->getIndex();
-        BZDB.setInt("multisample", (multi == 0)?0:(int)pow(2, multi));
+        BZDB.setInt("multisample", (int)pow(2, multi));
         break;
     }
     case 'g':