Fix test ordering failures.

The `:jobs` queue needs to be cleared before these tests because they
assert on the size of the `:jobs` queue. In some test orderings these
examples would fail.

Author: panthomakos

test/job_hooks_test.rb

@@ -252,6 +252,8 @@ def self.perform(history)
 
 
 describe "Resque::Job before_enqueue" do
+  before{ Resque.redis.flushall }
+
   include PerformJob
 
   class ::BeforeEnqueueJob