Add to Suggests the packages that handlers need.

Seems like this has been our intent but was not updated that much recently.

debian/control

@@ -20,11 +20,15 @@ Depends:
  bsd-mailx | mailx | mailutils,
  ${misc:Depends}
 Suggests:
+ bzip2,
  debconf-utils,
+ duplicity,
  genisoimage,
  hwinfo,
  mdadm,
  rdiff-backup,
+ rsync,
+ subversion,
  wodim
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