Bug#866121: add Depends gvfs-backends

[積丹尼 Dan Jacobson]

Package: epiphany-browser
Version: 3.22.7-1

Add Depends: gvfs-backends
or else right out of the box
$ epiphany
will produce error messages and the add blocker won't work.

Or, just add it as a Recommends,
but be sure the default in the user's initial Preferences is to have
adblocking disabled.

See https://bugzilla.gnome.org/show_bug.cgi?id=784170