Update Debian packaging for 2.1.0

abigail 1.8 and newer is incompatible with the *.abi files shipped by
upstream with zfs 2.1.0. It must be downgraded to an older version.
buster shipped with abigail 1.5, which works fine, whereas bullseye
ships with 1.8.  This will probably be resolved with 2.1.1.
See here for details:
openzfs#12360

Several manpages were renamed, added or removed.  Their copyright
entries are updated herein but many other copyright entries seem
out of date and require updating as well.

Signed-off-by: Lukas Wunner <lukas@wunner.de>

debian/changelog

@@ -1,3 +1,9 @@
+zfs-linux (2.1.0-1) UNRELEASED; urgency=medium
+
+  * New upstream version 2.1.0
+
+ -- Lukas Wunner <lukas@wunner.de>  Mon, 23 Aug 2021 23:10:55 +0200
+
 zfs-linux (2.0.3-9) unstable; urgency=medium
 
   * Cherry-pick "Remove iov_iter_advance() for iter_write" (Closes: #989373)

debian/control

@@ -5,7 +5,7 @@ Maintainer: Debian ZFS on Linux maintainers <pkg-zfsonlinux-devel@alioth-lists.d
 Uploaders: Aron Xu <aron@debian.org>,
            Carlos Alberto Lopez Perez <clopez@igalia.com>,
            Mo Zhou <lumin@debian.org>
-Build-Depends: abigail-tools,
+Build-Depends: abigail-tools (<< 1.8),
                debhelper-compat (= 12),
                dh-python,
                dkms (>> 2.1.1.2-5),

debian/copyright

@@ -398,18 +398,32 @@ Copyright: 2009, Oracle and/or its affiliates.
   2009, Michael Gebetsroither <michael.geb@gmx.at>
 License: CDDL-1.0
 
-Files: man/man5/zfs-events.5
-       man/man5/zfs-module-parameters.5
+Files: man/man4/spl.4
 Copyright: 2013, Turbo Fredriksson <turbo@bayour.com>
 License: CDDL-1.0
 
-Files: man/man5/zpool-features.5
+Files: man/man4/zfs.4
+Copyright: 2013, Turbo Fredriksson <turbo@bayour.com>
+  2019, 2021, Delphix
+  2019, Datto Inc.
+License: CDDL-1.0
+
+Files: man/man7/zpool-features.7
 Copyright:
   2013, Delphix
   2013, Saso Kiselkov
   2014, Joyent, Inc.
 License: CDDL-1.0
 
+Files: man/man8/zpool-events.8
+Copyright: 2007, Sun Microsystems, Inc.
+  2012, 2018, Delphix
+  2012, Cyril Plisko
+  2017, Datto Inc.
+  2018, George Melikov
+  2017, Nexenta Systems, Inc.
+  2017, Open-E, Inc.
+
 Files: man/man8/zdb.8
 Copyright: 2012, Richard Lowe.
   2012, Delphix
@@ -426,10 +440,6 @@ Copyright: 2007, Sun Microsystems, Inc.
   2013, Delphix
 License: CDDL-1.0
 
-Files: man/man8/zstreamdump.8
-Copyright: 2009, Sun Microsystems, Inc.
-License: CDDL-1.0
-
 Files: module/*
 Copyright: 2011-2014, Delphix.
   2007, 2009, 2010, Sun Microsystems, Inc.