Couple new compiler warnings

[Daniel J Sebald]

  CXX    graphics/graphics_libgui_graphics_la-Canvas.lo
/libgui/graphics/Canvas.cc:309:1: warning: 'bool 
QtHandles::rotate_enabled(graphics_object)' defined but not used
/libgui/graphics/Canvas.cc:345:1: warning: 'std::string 
QtHandles::zoom_direction(graphics_object)' defined but not used

The compiler is probably complaining because these are defined with the 
static variable and can't be removed by the compiler as an unused 
non-static member function could be, i.e., unused code space.  "#ifdef 
0" around the unused functions should do it.

Dan