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.
#require rust
$ cat >> $HGRCPATH << EOF
> [format]
> use-dirstate-v2=1
> [storage]
> dirstate-v2.slow-path=allow
> EOF
$ hg init t
$ cd t
$ for i in 1 2 3 4 5 6 7 8 9 10; do touch foobar$i; done
$ hg add .
adding foobar1
adding foobar10
adding foobar2
adding foobar3
adding foobar4
adding foobar5
adding foobar6
adding foobar7
adding foobar8
adding foobar9
$ hg commit -m "1"
Check that there's no space leak on debugrebuilddirstate
$ f --size .hg/dirstate*
.hg/dirstate: size=133
.hg/dirstate.88698448: size=511
$ hg debugrebuilddirstate
$ f --size .hg/dirstate*
.hg/dirstate: size=133
.hg/dirstate.6b8ab34b: size=511
$ hg debugrebuilddirstate
$ f --size .hg/dirstate*
.hg/dirstate: size=133
.hg/dirstate.b875dfc5: size=511