fix building problem with deprecated gnome_keyring

Adding patch from:
https://git.gnome.org/browse/network-manager-pptp/commit/?id=d291de33c58d8394c97d9389a677ca75468a5599
and
https://git.gnome.org/browse/network-manager-pptp/commit/?id=33615b8aa6f71a8e8765ee015948e9634003f887

for fix building problem with deprecated gnome_keyring


auth-dialog/vpn-password-dialog.c - оставлен сам фаил, т.к. он в po файлах указан