Set refspecs in clone so that future fetch does not need to be fast-forwarding

I had a cloned samba repository where I decided to run "git fetch pkg", and was surprised to get rejections on branches that I never even checked out:

(ubuntu/devel)andreas@nsnx:~/git/packages/samba$ git fetch pkg
remote: Counting objects: 311, done.
remote: Compressing objects: 100% (26/26), done.
remote: Total 311 (delta 280), reused 310 (delta 279)
Receiving objects: 100% (311/311), 310.20 KiB | 446.00 KiB/s, done.
Resolving deltas: 100% (280/280), completed with 249 local objects.
From https://git.launchpad.net/~usd-import-team/ubuntu/+source/samba
 ! [rejected] applied/debian/buster -> pkg/applied/debian/buster (non-fast-forward)
 ! [rejected] debian/buster -> pkg/debian/buster (non-fast-forward)
   7511daf27..48b55da31 debian/sid -> pkg/debian/sid
   c80fbe820..af32ae260 importer/debian/dsc -> pkg/importer/debian/dsc
   3367af40b..33a132b4d importer/debian/pristine-tar -> pkg/importer/debian/pristine-tar
 * [new tag] import/2%4.7.1+dfsg-1 -> pkg/import/2%4.7.1+dfsg-1
 * [new tag] upstream/debian/4.7.1+dfsg.gz -> pkg/upstream/debian/4.7.1+dfsg.gz

I ended up doing "git fetch pkg --force". Nish said this:

"we need to set the refspecs *in* clone so that future fetch does nnot need to be fast-forwarding"