Add ability to filter ginkgo tests

So that we can only run the updates test when it's time
to promote.

[#152219347]https://www.pivotaltracker.com/story/show/152219347

Signed-off-by: Natalie Arellano <[email protected]>

Author: Stu Pollock

lib/tasks/run/bwats.rake

@@ -31,7 +31,7 @@ namespace :run do
     if ENV["USE_RETRIES"].to_s == 'true'
       ginkgo_command += " --flakeAttempts=3"
     end
-    ginkgo_command += " -r -v #{test_path}"
+    ginkgo_command += " -r -v #{test_path} --filter=\"#{ENV["GINKGO_FOCUS"]}\""
     exec_command(ginkgo_command)
   end
 end