g_local_file_trash: remove invalid free call

Commit 8ece2de964 transplanted a block of
code that contained an early-exit-on-error case which freed several
variables.

Because of the move, the normal-path unconditional free of one of these
variables is now above this early exit case, so if this block is hit, it
will now be a double-free.

Remove that.

https://bugzilla.gnome.org/show_bug.cgi?id=757693

gio/glocalfile.c

@@ -2144,7 +2144,6 @@ g_local_file_trash (GFile         *file,
 
       g_unlink (infofile);
 
-      g_free (topdir);
       g_free (trashname);
       g_free (infofile);
       g_free (trashfile);