Avoid failing if delete_matched try delete too much data

Ruby cannot accept method with args more than 131_000. To avoid a
StackLevelTooDeep exception, we need limit the number of args pass to
@redis.del(*args)

This case is really an edge but can arrived because, I have this issue in my application sometimes.

An example of code with this failing is do on this gist : https://gist.github.com/4620006