CmdProjects: Enforce garbage collector

ChangeLog

@@ -1,5 +1,7 @@
 2.4.2 () -
 
+- TW-1450 Projects command should trigger running garbage collector (thanks to
+          Tomas Babej).
 - TW-1535 move default listing-break from list to ls (thanks to David Patrick).
 - TW-1545 cc1plus: error: unrecognized command line option '-std=c++11' (thanks
           to Petteri).

src/commands/CmdProjects.cpp

@@ -53,6 +53,9 @@ int CmdProjects::execute (std::string& output)
 {
   int rc = 0;
 
+  // Enforce the garbage collector to show correct task counts
+  context.tdb2.gc ();
+
   // Get all the tasks.
   handleRecurrence ();
   std::vector <Task> tasks = context.tdb2.pending.get_tasks ();