revset: have rev() validate input by repo.changelog.__contains__()
fullreposet.__contains__() will be rewritten in order to support "null"
revision, and "rev()" won't be possible to rely on it.
This backs out eb763217152a, but there is no performance regression now.
revisions:
0) e1dbe0b215ae "l not in fullreposet(repo)"
1) this patch "l not in repo.changelog"
revset #0: rev(210000)
0) wall 0.000056 comb 0.000000 user 0.000000 sys 0.000000 (best of 48036)
1) wall 0.000049 comb 0.000000 user 0.000000 sys 0.000000 (best of 54969)