Merge remote-tracking branch 'origin/pr/446'

* origin/pr/446:
  appmenu_select: remove --i-understand-format-is-unstable flag

Pull request description:

The `--i-understand-format-is-unstable` flag is no longer needed after QubesOS/qubes-desktop-linux-common#72 removed the unstable-format gate for `--get-available`. Remove the now-redundant flag from the command invocation.

Author: marmarek

qubesmanager/appmenu_select.py

@@ -96,7 +96,6 @@ def fill_apps_list(self, template=None):
         command = [
             "qvm-appmenus",
             "--get-available",
-            "--i-understand-format-is-unstable",
             "--file-field",
             "Comment",
             "--file-field",