storage_service: Remove write-only _force_remove_completion

This boolean became effectively unused after 829b4c14 (repair:
Make removenode safe by default)

Signed-off-by: Pavel Emelyanov <xemul@scylladb.com>

service/storage_service.cc

@@ -3633,10 +3633,7 @@ future<> storage_service::force_remove_completion() {
                 // This flag will make removenode stop waiting for the confirmation,
                 // wait it to complete
                 slogger.info("Operation removenode is in progress, wait for it to complete");
-
-                ss._force_remove_completion = true;
                 sleep_abortable(std::chrono::seconds(1), ss._abort_source).get();
-                ss._force_remove_completion = false;
             }
             ss._operation_in_progress = sstring("removenode_force");
 

service/storage_service.hh

@@ -188,7 +188,6 @@ private:
     // ever arise.
     bool _loading_new_sstables = false;
     sstring _operation_in_progress;
-    bool _force_remove_completion = false;
     bool _ms_stopped = false;
     bool _stream_manager_stopped = false;
     seastar::metrics::metric_groups _metrics;