Bug#405094: kleopatra: depends on lower priority (extra) package (gnupg2)

[Filipus Klutiero <chealer@zanzibar.vif.com>]

Package: kleopatra
Version: 4:3.5.5.dfsg.1-4
Severity: normal

kleopatra shouldn't be optional and have a dependency on an extra
package, gnupg2, to avoid violating policy 2.5.