gnu: Remove zbackup.

* gnu/packages/backup.scm (zbackup): Delete variable.

Fixes: guix/guix#3822
Change-Id: I067b8df90910444136ee6ca65148c26ba524697c

gnu/packages/backup.scm

@@ -1001,38 +1001,6 @@ restic's REST backend API.  It provides a secure and efficient way to backup
 data remotely, using the restic backup client and a @code{rest:} URL.")
     (license license:bsd-2)))
 
-(define-public zbackup
-  (package
-    (name "zbackup")
-    (version "1.4.4")
-    (source
-     (origin
-       (method git-fetch)
-       (uri (git-reference
-             (url "https://github.com/zbackup/zbackup")
-             (commit version)))
-       (file-name (git-file-name name version))
-       (sha256
-        (base32 "14l1kyxg7pccpax3d6qcpmdycb70kn3fxp1a59w64hqy2493hngl"))))
-    (build-system cmake-build-system)
-    (arguments
-     `(#:tests? #f))                    ;no test
-    (inputs
-     (list lzo libressl protobuf-3.6 xz zlib))
-    (home-page "http://zbackup.org")
-    (synopsis "Versatile deduplicating backup tool")
-    (description
-     "ZBackup is a globally-deduplicating backup tool, based on the
-ideas found in Rsync.  Feed a large @file{.tar} into it, and it will
-store duplicate regions of it only once, then compress and optionally
-encrypt the result.  Feed another @file{.tar} file, and it will also
-re-use any data found in any previous backups.  This way only new
-changes are stored, and as long as the files are not very different,
-the amount of storage required is very low.  Any of the backup files
-stored previously can be read back in full at any time.  The program
-is format-agnostic, so you can feed virtually any files to it.")
-    (license license:gpl2+)))
-
 (define-public dump
   (package
     (name "dump")