tree: Remove custom clearing macros

The macros was emulating g_clear_handle_id() and friends
let's use the glib functions directly instead.

Part-of: <https://gitlab.gnome.org/GNOME/calls/-/merge_requests/755>

src/calls-util.h

@@ -89,13 +89,6 @@ G_BEGIN_DECLS
   CALLS_DEFINE_IFACE_GETTER_BASE(calls,iface,Calls,Iface,CALLS,IFACE,prop,rettype,errval)
 
 
-#define calls_clear_source(source_id_ptr)       \
-  if (*source_id_ptr != 0)                      \
-    {                                           \
-      g_source_remove (*source_id_ptr);         \
-      *source_id_ptr = 0;                       \
-    }
-
 #define calls_clear_signal(object,handler_id_ptr)               \
   if (*handler_id_ptr != 0)                                     \
     {                                                           \
@@ -103,13 +96,6 @@ G_BEGIN_DECLS
       *handler_id_ptr = 0;                                      \
     }
 
-#define calls_date_time_unref(date_time)        \
-  if (date_time)                                \
-    {                                           \
-      g_date_time_unref (date_time);            \
-    }
-
-
 
 gboolean    calls_date_time_is_same_day  (GDateTime  *a,
                                            GDateTime *b);