Merge pull request diffblue#130 from diffblue/marek/tpg_bugfix_PR

Bug-fix: forgotten update of the comment.

Author: marek-trtik

src/taint-analysis/taint_tokens_propagation_graph.h

@@ -58,7 +58,7 @@ class taint_tokens_propagation_grapht
 
   // To track references of input and output parameters of individual rules.
   // The "return_value" value in the output map is denoted by -1. The values
-  // 999 (see the static method 'get_void_loc()') means 'no value', i.e. it
+  // -2 (see the static method 'get_void_loc()') means 'no value', i.e. it
   // is a dummy reference, typically related to SOURCE and SINK nodes.
   typedef std::map<rule_idt, std::vector<int>>
           map_from_rules_to_inputst;