Disable the encrypted and signed checkboxes if the dialog is read only.
Disable the encrypted and signed checkboxes if the dialog is read only.

svn path=/trunk/kdenetwork/kmail/; revision=170795

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