migration: Rename RAMStats to MigrationAtomicStats

It is lousely based on MigrationStats, but that name is taken, so this
is the best one that I came with.

Signed-off-by: Juan Quintela <quintela@redhat.com>
Reviewed-by: Lukas Straub <lukasstraub2@web.de>

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If you have any good suggestion for the name, I am all ears.
2 files changed