always set up plugin symlinks b4 compiling sass
always set up plugin symlinks b4 compiling sass

Fixes: CORE-352

Test plan:
* in a deployers vm (or somewhere where you don’t have a full
  Rails environment set up with a database connection and everything)
* run compile_assets
* you should see some `compiled plugins/analytics/analytics.scss …`
  output in your console
* `grep analytics public/dist/brandable_css/*bundles_with_deps.*`
  Should have stuff about analytics

Change-Id: Ifaa17c42f5fc62a911a84febbb674c2bb570db37
Reviewed-on: https://gerrit.instructure.com/131123
Reviewed-by: Cody Cutrer <c4fe2b1d90ef8f2548c8aeabfa633434316f0305@instructure.com>
Tested-by: Jenkins
Product-Review: Ryan Shaw <ea3cd978650417470535f3a4725b6b5042a6ab59@instructure.com>
QA-Review: Ryan Shaw <ea3cd978650417470535f3a4725b6b5042a6ab59@instructure.com>

djbender/canvas-lms,djbender/canvas-lms,venturehive/canvas-lms,sfu/canvas-lms,sfu/canvas-lms,venturehive/canvas-lms,sfu/canvas-lms,sfu/canvas-lms,djbender/canvas-lms,sfu/canvas-lms,venturehive/canvas-lms,sfu/canvas-lms,djbender/canvas-lms,sfu/canvas-lms,venturehive/canvas-lms