change instance variables to method calls

these instance variables are no longer available on Rails 4.  We should
use the accessor methods instead.
Remove reference to no longer needed host version
Don't show full backtrace for rspec failures

Instead, we'll just manipulate the default filter patterns. We still
want to exclude rspec, ruby stdlib, and released gems... but in contrast
to its default behaviour, we should still show lines for bundler-
vendored gems.
Fix OpenStack images pagination

Pagination is always forced by Glance conf file. So we
need to always obtain all pages of images in cycle.

Depends-On: https://github.com/fog/fog/pull/3321
Depends-On: https://github.com/fog/fog/pull/3322

https://bugzilla.redhat.com/show_bug.cgi?id=1164764
Merge pull request #1235 from matthewd/quiet-rspec

Don't show full backtrace for rspec failures
Merge pull request #1240 from JPrause/fix_tar_creation

Remove reference to no longer needed host version
Merge pull request #1198 from Ladas/openstack_fix_images_pagination

Fix OpenStack images pagination
Merge pull request #1233 from tenderlove/methods

change instance variables to method calls