Revert "Fix updates notification on Fedora 29"

The https://bugzilla.redhat.com/1650446 is fixed for enough time already
(included in all supported distributions). The workaround for the bug
have two issues:
 - may download repository metadata again
 - ignores various settings, including proxy, which breaks it in
   TemplateVM

This reverts commit 8d7313b928.

package-managers/dnf-qubes-hooks.py

@@ -59,18 +59,6 @@ class QubesHooks(dnf.Plugin):
             config = self.read_config(self.base.conf)
 
         if config.getboolean('main', 'notify-updates'):
-            if LooseVersion(dnf.const.VERSION) > '4.0.0':
-                # self.base.transaction empty at this point in dnf4
-                # https://bugzilla.redhat.com/1650446
-                # until fixed, load the repositories again and again check for
-                # updates
-                base = dnf.Base()
-                base.read_all_repos()
-                base.fill_sack()
-                query = base.sack.query()
-                query = query.upgrades()
-                updates = set(query.run())
-            else:
             # Get all updates available _before_ this transaction
             query = self.base.sack.query()
             query = query.upgrades()