mem-ruby: bug fix for Finish_CopyBack_Stale

I made a mistake in the change below:
https://gem5-review.googlesource.com/c/public/gem5/+/58413

Checking the requestor in the sharer list for eviction
should be removed now. If the sharer count is zero, the requestor can't
be in the sharer list.

Change-Id: I304d2dd7df1aff4907801664a260c35c490a2136
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/62991
Maintainer: Jason Lowe-Power <power.jg@gmail.com>
Tested-by: kokoro <noreply+kokoro@google.com>
Reviewed-by: Jason Lowe-Power <power.jg@gmail.com>
1 file changed