fix initialization

src/Storages/MergeTree/ReplicatedMergeTreeQueue.h

@@ -154,7 +154,7 @@ private:
     std::map<String, MutationStatus> mutations_by_znode;
 
     /// Unfinished mutations that are required for AlterConversions.
-    Int64 num_alter_conversions;
+    Int64 num_alter_conversions = 0;
 
     /// Partition -> (block_number -> MutationStatus)
     std::unordered_map<String, std::map<Int64, MutationStatus *>> mutations_by_partition;

src/Storages/StorageMergeTree.h

@@ -150,7 +150,7 @@ private:
     std::map<UInt64, MergeTreeMutationEntry> current_mutations_by_version;
 
     /// Unfinished mutations that are required for AlterConversions.
-    Int64 num_alter_conversions;
+    Int64 num_alter_conversions = 0;
 
     std::atomic<bool> shutdown_called {false};
     std::atomic<bool> flush_called {false};