Don't create an invalidated surface when not needed

After invalidateSurface() is called we don't want to recreate
the EGLSurface on setGeometry() until makeCurrent is called

Change-Id: Ide10ecf3bff40a01fa1ed249986a631c77c2bf63
Reviewed-by: Gunnar Sletta <gunnar.sletta@jollamobile.com>