Fix periodic backup saves

Retain ".pending" files until explicit save or session destruction.
Previously every transport-stop deleted them :(

libs/ardour/session.cc

@@ -2088,10 +2088,6 @@ Session::disable_record (bool rt_context, bool force)
 		}
 
 		RecordStateChanged (); /* emit signal */
-
-		if (!rt_context) {
-			remove_pending_capture_state ();
-		}
 	}
 }
 

libs/ardour/session_state.cc

@@ -449,7 +449,6 @@ Session::session_loaded ()
 		save_state ("");
 	} else if (state_was_pending) {
 		save_state ("");
-		remove_pending_capture_state ();
 		state_was_pending = false;
 	}
 
@@ -818,6 +817,10 @@ Session::save_state (string snapshot_name, bool pending, bool switch_to_snapshot
 		fork_state = switch_to_snapshot ? SwitchToSnapshot : SnapshotKeep;
 	}
 
+	if (!pending && !for_archive && ! template_only) {
+		remove_pending_capture_state ();
+	}
+
 #ifndef NDEBUG
 	const int64_t save_start_time = g_get_monotonic_time();
 #endif

libs/ardour/session_transport.cc

@@ -1724,10 +1724,6 @@ Session::non_realtime_stop (bool abort, int on_entry, bool& finished)
 		}
 	}
 
-	/* always try to get rid of this */
-
-	remove_pending_capture_state ();
-
 	/* save the current state of things if appropriate */
 
 	if (did_record && !saved) {