macosx: do not create VLCVoutController twice, remove singleton

The only valid instance of the vout controller is owned by VLCMain.

modules/gui/macosx/VLCVoutWindowController.h

@@ -32,8 +32,6 @@
 
 @interface VLCVoutWindowController : NSObject
 
-+ (VLCVoutWindowController *)sharedInstance;
-
 @property (readonly, atomic) NSLock *lock;
 
 @property (readonly, nonatomic) NSInteger currentStatusWindowLevel;

modules/gui/macosx/VLCVoutWindowController.m

@@ -211,18 +211,6 @@ void WindowClose(vout_window_t *p_wnd)
 
 @implementation VLCVoutWindowController
 
-+ (VLCVoutWindowController *)sharedInstance
-{
-    static VLCVoutWindowController *sharedInstance = nil;
-    static dispatch_once_t pred;
-
-    dispatch_once(&pred, ^{
-        sharedInstance = [VLCVoutWindowController new];
-    });
-
-    return sharedInstance;
-}
-
 - (id)init
 {
     self = [super init];

modules/gui/macosx/intf.m

@@ -86,8 +86,6 @@ int OpenIntf (vlc_object_t *p_this)
         [NSBundle loadNibNamed:@"MainWindow" owner:[VLCMain sharedInstance]];
         [[[VLCMain sharedInstance] mainWindow] makeKeyAndOrderFront:nil];
 
-        [VLCVoutWindowController sharedInstance];
-
         return VLC_SUCCESS;
     }
 }