Get rid of unnecessary wxColour::InitFromComponents() in wxOSX

This method was confusing and dangerous as it didn't actually initialize the
wxColour object because it didn't set its m_cgColour and so attempting to use
wxColour "initialized" using this method resulted in a crash whenever its
GetPixel(), GetCGColor() or CreateCGColor() methods were called.

Just merge this function with InitCGColorRef() which is the only remaining
place where it's used after rewriting wxColour(NSColor) ctor.

include/wx/osx/core/colour.h

@@ -72,7 +72,7 @@ protected :
     void InitRGBColor( const RGBColor& col );
 #endif
     void InitCGColorRef( CGColorRef col );
-    void InitFromComponents(const CGFloat* components, size_t numComponents );
+
 private:
     wxCFRef<CGColorRef>     m_cgColour;