config: use the new '_unset' value for 'configpath'
This should let 'configpath' delegate all special processing of the default
config value to the main 'config' method.
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" | \
cat
}