Revert "update rspec to work with ruby 1.8.7"

This reverts commit 9fe8511ec88ba6f8c009b9602a63bb4d08a92fef.
update rspec to work with ruby 1.8.7

The compat issue was merely a dangling comma so this fix is much less
crude than 9fe8511ec88ba6f8c009b9602a63bb4d08a92fef.