tests(clustering): errors spec only for sync.v1

spec/02-integration/09-hybrid_mode/12-errors_spec.lua

@@ -69,8 +69,7 @@ local function get_error_report(client, msg)
 end
 
 
--- XXX TODO: mock_cp does not support rpc sync rpc
-for _, rpc_sync in ipairs { "off"  } do
+-- these tests are only for sync v1
 for _, strategy in helpers.each_strategy() do
   describe("CP/DP sync error-reporting with #" .. strategy .. " rpc_sync=" .. rpc_sync .. " backend", function()
     local client
@@ -102,7 +101,7 @@ for _, strategy in helpers.each_strategy() do
         -- use a small map size so that it's easy for us to max it out
         lmdb_map_size               = "1m",
         plugins                     = "bundled,cluster-error-reporting",
-        cluster_rpc_sync = rpc_sync,
+        cluster_rpc_sync            = "off",
       }, nil, nil, fixtures))
     end)
 
@@ -260,4 +259,3 @@ for _, strategy in helpers.each_strategy() do
     end)
   end)
 end -- for _, strategy
-end -- for rpc_sync