gvfs: fix CVE-2019-12795

This is a version of #63481 for master.

Vulnerability Description:
daemon/gvfsdaemon.c in gvfsd from GNOME gvfs before 1.38.3, 1.40.x before
1.40.2, and 1.41.x before 1.41.3 opened a private D-Bus server socket without
configuring an authorization rule. A local attacker could connect to this server
socket and issue D-Bus method calls. Note that the server socket only accepts
a single connection, so the attacker would have to discover the server and connect
to the socket before its owner does.

#63301