Remove event handler no longer needed

The custom handler for "URL changed" events were added to reload the
file list whenever the sections for favorites and shares were opened;
this was used to fix the problem of not reloading the file lists when
opening them for a second time. However, besides that the handlers were
not really necessary, and as the root of the bug was fixed in the
previous commit those handlers are now removed.

The file list for tags uses the handler for a different purpose, though,
so that one was kept.

Signed-off-by: Daniel Calviño Sánchez <danxuliu@gmail.com>