trivial diff: Documentation fix in dependency_graph.m

[Andrew Bromage]

There is no need to review.  Changes already committed.

Estimated hours taken: 0.1

compiler/dependency_graph.m:
	Remove some documentation which is completely untrue, and
	seems to be from liveness.m (probably because of a bad
	cut-and-paste).

	Change copyright year.

Index: dependency_graph.m
===================================================================
RCS file: /home/staff/zs/imp/mercury/compiler/dependency_graph.m,v
retrieving revision 1.32
diff -u -r1.32 dependency_graph.m
--- dependency_graph.m	1997/12/23 06:58:49	1.32
+++ dependency_graph.m	1998/01/01 06:13:41
@@ -1,5 +1,5 @@
 %-----------------------------------------------------------------------------%
-% Copyright (C) 1995-1997 The University of Melbourne.
+% Copyright (C) 1995-1998 The University of Melbourne.
 % This file may only be copied under the terms of the GNU General
 % Public License - see the file COPYING in the Mercury distribution.
 %-----------------------------------------------------------------------------%
@@ -171,10 +171,6 @@
 %-----------------------------------------------------------------------------%
 %-----------------------------------------------------------------------------%
 
-% The call_info structure (map(var, lval)) is threaded through the traversal
-% of the goal. The liveness information is computed from the liveness
-% delta annotations.
-
 :- pred dependency_graph__add_arcs_in_goal(hlds_goal, relation_key,
 					dependency_graph, dependency_graph).
 :- mode dependency_graph__add_arcs_in_goal(in, in, in, out) is det.
@@ -184,9 +180,6 @@
 	dependency_graph__add_arcs_in_goal_2(Goal, PPId, DepGraph0, DepGraph).
 
 %-----------------------------------------------------------------------------%
-	% Here we process each of the different sorts of goals.
-	% `Liveness' is the set of live variables, i.e. vars which
-	% have been referenced and will be referenced again.
 
 :- pred dependency_graph__add_arcs_in_goal_2(hlds_goal_expr, relation_key,
 					dependency_graph, dependency_graph).
@@ -219,6 +212,7 @@
 
 dependency_graph__add_arcs_in_goal_2(higher_order_call(_, _, _, _, _, _),
 		_Caller, DepGraph, DepGraph).
+
 dependency_graph__add_arcs_in_goal_2(class_method_call(_, _, _, _, _, _),
 		_Caller, DepGraph, DepGraph).