FIX: Don't reset the path explorer when not necessary

This will allow the path explorer to complete path exploration
for all categories. If it introduces any new bugs, they need to
be fixed more delicately than before.

simdepot.cc

@@ -195,7 +195,7 @@ void depot_t::convoi_arrived(convoihandle_t acnv, bool fpl_adjust)
 #ifdef MULTI_THREAD
 		world()->await_path_explorer();
 #endif
-		path_explorer_t::refresh_all_categories(true);
+		path_explorer_t::refresh_all_categories(false);
 	}
 
 	// Clean up the vehicles -- get rid of freight, etc.  Do even when loading, just in case.

simtool.cc

@@ -7388,7 +7388,7 @@ const char *tool_stop_mover_t::do_work( player_t *player, const koord3d &last_po
 #ifdef MULTI_THREAD
 		world()->await_path_explorer();
 #endif
-		path_explorer_t::refresh_all_categories(true);
+		path_explorer_t::refresh_all_categories(false);
 	}
 	return NULL;
 }

simworld.cc

@@ -2834,7 +2834,7 @@ void karte_t::enlarge_map(settings_t const* sets, sint8 const* const h_field)
 	await_path_explorer();
 #endif
 	// Modified by : Knightly
-	path_explorer_t::refresh_all_categories(true);
+	path_explorer_t::refresh_all_categories(false);
 
 	set_schedule_counter();
 
@@ -4451,7 +4451,7 @@ DBG_MESSAGE( "karte_t::rotate90()", "called" );
 
 	// finally recalculate schedules for goods in transit ...
 	// Modified by : Knightly
-	path_explorer_t::refresh_all_categories(true);
+	path_explorer_t::refresh_all_categories(false);
 
 	set_dirty();
 }
@@ -5129,7 +5129,7 @@ void karte_t::new_month()
 
 	// Added by : Knightly
 	// Note		: This should be done after all lines and convoys have rolled their statistics
-	path_explorer_t::refresh_all_categories(true);
+	path_explorer_t::refresh_all_categories(false);
 }
 
 
@@ -5685,7 +5685,7 @@ void karte_t::step()
 	// This is not the computationally intensive bit of the path explorer.
 	if((steps % get_settings().get_reroute_check_interval_steps()) == 0)
 	{
-		path_explorer_t::refresh_all_categories(true);
+		path_explorer_t::refresh_all_categories(false);
 	}
 
 	INT_CHECK("karte_t::step 8");