shelve: drop some weird manually stripping before transaction abort
I cannot find a case where this is actually useful, so lets triggering strip in
the middle of uncommitted transaction.
{
"conduit_uri": "https://phab.mercurial-scm.org/api",
"phabricator.uri": "https://phab.mercurial-scm.org/",
"repository.callsign": "HG",
"arc.land.onto.default": "@",
"base": "hg:.^"
}