ceph: Deduplicate the default

pkgs/tools/filesystems/ceph/default.nix

···
-{ callPackage, fetchgit, ... } @ args:
-
-callPackage ./generic.nix (args // rec {
-  version = "9.2.0";
-
-  src = fetchgit {
-    url = "https://github.com/ceph/ceph.git";
-    rev = "refs/tags/v${version}";
-    sha256 = "1lcal0jbpnm6y91s2v0g2zdnq7q0i5ql4bky294cz7g011di12vc";
-  };
-
-  patches = [ ./fix-pythonpath.patch ];
-})
+9.nix