remove unnecessary Timecop.return command

Fixes #275

Author: jakelandis

spec/inputs/jdbc_spec.rb

@@ -412,7 +412,6 @@
         event = queue.pop
         expect(event.get("num")).to eq(12)
         expect(event.get("custom_time").time).to eq(Time.iso8601("2015-01-02T03:21:21.000Z"))
-        Timecop.return
       end
     end