rbd: drop --pool option from "rbd group image {add,rm}"

It stopped working with removal of get_special_pool_group_names() in
commit 3e8624f ("rbd: add support for namespaces") over six years
ago.  Given how much time has passed, stop accepting this option.

Signed-off-by: Ilya Dryomov <[email protected]>

Author: idryomov

src/test/cli/rbd/help.t

@@ -916,7 +916,7 @@
                              [--group-namespace <group-namespace>] 
                              [--group <group>] [--image-pool <image-pool>] 
                              [--image-namespace <image-namespace>] 
-                             [--image <image>] [--pool <pool>] 
+                             [--image <image>] 
                              <group-spec> <image-spec> 
 
   Add an image to a group.
@@ -934,7 +934,6 @@
     --image-pool arg      image pool name
     --image-namespace arg image namespace name
     --image arg           image name
-    -p [ --pool ] arg     pool name unless overridden
 
   rbd help group image list
   usage: rbd group image list [--format <format>] [--pretty-format] 
@@ -960,8 +959,7 @@
                                 [--group-namespace <group-namespace>] 
                                 [--group <group>] [--image-pool <image-pool>] 
                                 [--image-namespace <image-namespace>] 
-                                [--image <image>] [--pool <pool>] 
-                                [--image-id <image-id>] 
+                                [--image <image>] [--image-id <image-id>] 
                                 <group-spec> <image-spec> 
 
   Remove an image from a group.
@@ -979,7 +977,6 @@
     --image-pool arg      image pool name
     --image-namespace arg image namespace name
     --image arg           image name
-    -p [ --pool ] arg     pool name unless overridden
     --image-id arg        image id
 
   rbd help group info

src/tools/rbd/action/Group.cc

@@ -964,9 +964,6 @@ void get_add_arguments(po::options_description *positional,
   add_prefixed_pool_option(options, "image");
   add_prefixed_namespace_option(options, "image");
   at::add_image_option(options, at::ARGUMENT_MODIFIER_NONE);
-
-  at::add_pool_option(options, at::ARGUMENT_MODIFIER_NONE,
-	       " unless overridden");
 }
 
 void get_remove_image_arguments(po::options_description *positional,
@@ -989,8 +986,6 @@ void get_remove_image_arguments(po::options_description *positional,
   add_prefixed_namespace_option(options, "image");
   at::add_image_option(options, at::ARGUMENT_MODIFIER_NONE);
 
-  at::add_pool_option(options, at::ARGUMENT_MODIFIER_NONE,
-	       " unless overridden");
   at::add_image_id_option(options);
 }