Disable Defer button when no deferral is possible
Disable Defer button when no deferral is possible

svn path=/branches/KDE/4.4/kdepim/; revision=1199363

lefou/kdepim-noakonadi,lefou/kdepim-noakonadi,lefou/kdepim-noakonadi,lefou/kdepim-noakonadi,lefou/kdepim-noakonadi,lefou/kdepim-noakonadi