Do not use user-own assign operator

Author: mattn

common/khronos_ocl_clhpp/cl2.hpp

@@ -1896,6 +1896,7 @@ struct ImageFormat : public cl_image_format
         image_channel_data_type = type;
     }
 
+#if 0
     //! \brief Assignment operator.
     ImageFormat& operator = (const ImageFormat& rhs)
     {
@@ -1905,6 +1906,7 @@ struct ImageFormat : public cl_image_format
         }
         return *this;
     }
+#endif
 };
 
 /*! \brief Class interface for cl_device_id.
@@ -2700,7 +2702,7 @@ class Context
                     error = platforms[i].getDevices(type, &devices);
 
 #if defined(CL_HPP_ENABLE_EXCEPTIONS)
-                } catch (Error) {}
+                } catch (Error&) {}
     // Catch if exceptions are enabled as we don't want to exit if first platform has no devices of type
     // We do error checking next anyway, and can throw there if needed
 #endif