Require active_support before core_ext to fix uninitialized constant.

Fixes travis error with linux_admin:
https://travis-ci.org/ManageIQ/linux_admin/builds/29519678

This is a known issue with activesupport and travis:
https://github.com/rails/rails/issues/14664

See also:
https://github.com/ManageIQ/polisher/commit/c899d500502a57582a906dfa20cc6cf343c09265
Merge pull request #103 from jrafanie/require_active_support_before_core_ext_to_fix_uninitialized_constant

Require active_support before core_ext to fix uninitialized constant
Fix issue where LinuxAdmin::Disk.local misses /dev/xvda

Fixes #97
Closes #100
Fix issue where Disk.create_partition causes parted to fail

Fixes #98
Closes #99