Please allow manual specification of bucket name when using s3 backend

[Wren Turkal]

It would be really nice to be able to set the bucket name manually without going into gconf. The current way I do this is like at the following link:
http://blog.domenech.org/2013/01/backing-up-ubuntu-using-deja-dup-backup-and-aws-s3.html

I think it would be better if that could be changed from within the Backups section within the unity system settings app.

It would also be nice if specifying a region were posssible.

Info:
$ lsb_release -d
Description: Ubuntu 15.04

$ dpkg-query -W deja-dup duplicity
deja-dup 32.0-0ubuntu5
duplicity 0.7.01-1ubuntu1

$ cat /tmp/deja-dup.gsettings
org.gnome.DejaDup last-restore ''
org.gnome.DejaDup periodic false
org.gnome.DejaDup full-backup-period 90
org.gnome.DejaDup backend 's3'
org.gnome.DejaDup last-run '2015-04-29T20:51:06.302045Z'
org.gnome.DejaDup nag-check '2015-03-04T21:29:43.339567Z'
org.gnome.DejaDup prompt-check '2015-03-02T19:41:30.133910Z'
org.gnome.DejaDup root-prompt true
org.gnome.DejaDup include-list ['$HOME']
org.gnome.DejaDup exclude-list ['$TRASH', '$DOWNLOAD', '/home/wt/.cache']
org.gnome.DejaDup last-backup '2015-04-29T20:51:06.302045Z'
org.gnome.DejaDup periodic-period 1
org.gnome.DejaDup delete-after 182
org.gnome.DejaDup.S3 id '<NOT_REAL>'
org.gnome.DejaDup.S3 bucket 'example-bucket'
org.gnome.DejaDup.S3 folder 'example-folder'