revlog: unify flag processing when loading index
The new code use a simple declaration to do centralised processing. This is
clearer, shorter and less error prone. This will be especially useful as we plan
to add a fourth format: changelog-v2.
Differential Revision: https://phab.mercurial-scm.org/D10622
#require test-repo jshint hg10
$ . "$TESTDIR/helpers-testrepo.sh"
run jshint on all tracked files ending in .js except vendored dependencies
$ cd "`dirname "$TESTDIR"`"
$ testrepohg locate 'set:**.js' \
> 2>/dev/null \
> | xargs jshint