tests/histedit-helpers.sh

subrepo: factor out Git version check to add doctests

Followup to 6a2acb0d9352::e5641536e4d5.

fixbundle() {
    grep -v 'saving bundle' | grep -v 'saved backup' | \
        grep -v added | grep -v adding | \
        grep -v "unable to find 'e' for patching" | \
        grep -v "e: No such file or directory"
}