bundle: do no check the changegroup version if no changegroup is included
We don't need to check the compatibility of something we will not use.
In practice this was getting in the was of `streamv2` bundles on a narrow
repository as the 'cg.version=02' value was rejected by this checks.
$ cat >> $HGRCPATH << EOF
> [extensions]
> strip=
> EOF
Setup repo
$ hg init repo
$ cd repo
Test backups list and recover
$ hg debugbackupbundle
no backup changesets found
$ mkcommit() {
> echo "$1" > "$1"
> hg add "$1"
> hg ci -l $1
> }
$ mkcommit a
$ mkcommit b
$ hg strip .
0 files updated, 0 files merged, 1 files removed, 0 files unresolved
saved backup bundle to $TESTTMP/repo/.hg/strip-backup/d2ae7f538514-2953539b-backup.hg
$ hg debugbackupbundle
Recover changesets using: hg debugbackupbundle --recover <changeset hash>
Available backup changesets:
* (glob)
d2ae7f538514 b
$ hg debugbackupbundle --recover d2ae7f538514
Unbundling d2ae7f538514
adding changesets
adding manifests
adding file changes
added 1 changesets with 1 changes to 1 files
new changesets d2ae7f538514 (1 drafts)