Fix modify-pool -s PG_SIZE without --pg_minsize

src/cmd/cli_pool_cfg.cpp

@@ -44,10 +44,10 @@ std::string validate_pool_config(json11::Json::object & new_cfg, json11::Json ol
         new_cfg["parity_chunks"] = parity_chunks;
     }
 
-    if (old_cfg.is_null() && new_cfg["scheme"].string_value() == "")
+    if (new_cfg["scheme"].string_value() == "")
     {
         // Default scheme
-        new_cfg["scheme"] = "replicated";
+        new_cfg["scheme"] = old_cfg.is_null() ? "replicated" : old_cfg["scheme"];
     }
     if (new_cfg.find("pg_minsize") == new_cfg.end() && (old_cfg.is_null() || new_cfg.find("pg_size") != new_cfg.end()))
     {

tests/test_failure_domain.sh

@@ -35,4 +35,6 @@ $ETCDCTL get --prefix /vitastor/pg/config --print-value-only | \
 build/src/cmd/vitastor-cli --etcd_address $ETCD_URL create-pool size1pool -s 1 -n 1 --force
 wait_condition 10 "$ETCDCTL get --prefix /vitastor/pg/config --print-value-only | jq -s -e '.[0].items["'"'"2"'"'"]'"
 
+build/src/cmd/vitastor-cli --etcd_address $ETCD_URL modify-pool size1pool -s 2 --force
+
 format_green OK