engine: pass upgrade operation inside _clonerevlogs()
Better to pass the operation instead of passing three of it's members (one of
the them is a function call) separately.
This will also be useful in future when we will like to control which things are
upgraded.
Differential Revision: https://phab.mercurial-scm.org/D9667
edition = "2018"
max_width = 79
wrap_comments = true
error_on_line_overflow = true