(FrameBuffer) Add Attachment enum boolean operator to allow it being used as a bool expression
(FrameBuffer) Add Attachment enum boolean operator to allow it being used as a bool expression

Fixes an SVACE error as well.

Change-Id: Icfb3a970753b2a558854176e24580a222e8d6e2c

dalihub/dali-core,dalihub/dali-core,dalihub/dali-core,dalihub/dali-core