bump ruby-saml-mod to 0.1.29

refs OPS-170

Change-Id: Iec3f9064b40b12fbf801cc80e5052efa1a018f6f
Reviewed-on: https://gerrit.instructure.com/36602
Reviewed-by: Brian Palmer <brianp@instructure.com>
Tested-by: Jenkins <jenkins@instructure.com>
Product-Review: Paul Hinze <paulh@instructure.com>
QA-Review: Paul Hinze <paulh@instructure.com>