Bug #905

- The problem was that the routine dependencyIsCircular() changed its behaviour
  in git revision 726fc33fe4, and the new version
  only checked tasks by id - but all completed/deleted tasks have the id0, which
  led to the problem.  The fix is extremelly simple, just get the dependencies
  by uuid instead of by id.

Signed-off-by: Paul Beckingham <paul@beckingham.net>

src/dependency.cpp

@@ -117,7 +117,7 @@ void dependencyGetBlocking (const Task& task, std::vector <Task>& blocking)
 bool dependencyIsCircular (const Task& task)
 {
   std::stack <Task> s;
-  std::vector <int> deps_current;
+  std::vector <std::string> deps_current;
 
   std::string task_uuid = task.get ("uuid");