Geary.Imap: Remove COMPRESS command

Geary hasn't used compression for IMAP in a while now due to the
possibility of information leakage for secure connections, so remove
the command as well.

po/POTFILES.in

@@ -238,7 +238,6 @@ src/engine/imap/command/imap-append-command.vala
 src/engine/imap/command/imap-capability-command.vala
 src/engine/imap/command/imap-close-command.vala
 src/engine/imap/command/imap-command.vala
-src/engine/imap/command/imap-compress-command.vala
 src/engine/imap/command/imap-copy-command.vala
 src/engine/imap/command/imap-create-command.vala
 src/engine/imap/command/imap-examine-command.vala

src/engine/imap/command/imap-compress-command.vala

@@ -1,22 +0,0 @@
-/* Copyright 2016 Software Freedom Conservancy Inc.
- *
- * This software is licensed under the GNU Lesser General Public License
- * (version 2.1 or later).  See the COPYING file in this distribution.
- */
-
-/**
- * See [[http://tools.ietf.org/html/rfc4978]]
- */
-
-public class Geary.Imap.CompressCommand : Command {
-
-    public const string NAME = "compress";
-
-    public const string ALGORITHM_DEFLATE = "deflate";
-
-
-    public CompressCommand(string algorithm, GLib.Cancellable? should_send) {
-        base(NAME, { algorithm }, should_send);
-    }
-
-}

src/engine/meson.build

@@ -100,7 +100,6 @@ engine_vala_sources = files(
   'imap/command/imap-capability-command.vala',
   'imap/command/imap-close-command.vala',
   'imap/command/imap-command.vala',
-  'imap/command/imap-compress-command.vala',
   'imap/command/imap-copy-command.vala',
   'imap/command/imap-create-command.vala',
   'imap/command/imap-delete-command.vala',