Install Tor from deb.torproject.org's stable repo.

The one we currently want (0.2.7) has been released as stable.

Will-Fix: #10604

config/chroot_apt/preferences

@@ -156,7 +156,7 @@ Pin: release o=Debian,n=jessie
 Pin-Priority: 990
 
 Package: *
-Pin: release o=TorProject,n=tor-experimental-0.2.7.x-jessie
+Pin: release o=TorProject,n=jessie
 Pin-Priority: 990
 
 Package: *

config/chroot_sources/torproject.chroot

-deb http://deb.torproject.org/torproject.org tor-experimental-0.2.7.x-jessie main
+deb http://deb.torproject.org/torproject.org jessie main
 deb http://deb.torproject.org/torproject.org sid main