mem-ruby: Fix for Invalid transition in MOESI_CMP_directory

mem-ruby: Fix for Invalid transition in MOESI_CMP_directory

Send the correct sharer count from the memory directory to the requesting
L2 cache in data message reply.

Jira issue: https://gem5.atlassian.net/browse/GEM5-613

Change-Id: If76de630fd0001816e8836d9bf77961a94faaa7c
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/29552
Maintainer: Jason Lowe-Power <power.jg@gmail.com>
Reviewed-by: Pouya Fotouhi <pfotouhi@ucdavis.edu>
Reviewed-by: Tiago Mück <tiago.muck@arm.com>
Reviewed-by: Jason Lowe-Power <power.jg@gmail.com>
Tested-by: kokoro <noreply+kokoro@google.com>