repoview: avoid wrapping changelog if there's nothing to filter...
repoview: avoid wrapping changelog if there's nothing to filter
This simplifies the code a bit by moving the optimizaton for no
filtered revisions to one place. I assume it also makes working with
repos without obsmarkers a little faster, but it doesn't seem
significant.
Differential Revision:
https://phab.mercurial-scm.org/D7248