Fix sortgroup function
Fix sortgroup function

This fixes an issue with the sortgroup function which failed to handle a
group line with only two colons correctly. Such group entries have been
seen in the wild on FreeBSD.

Also, comment lines in group files are now ignored (also seen on
FreeBSD).

arthurdejong/nss-pam-ldapd,arthurdejong/nss-pam-ldapd,arthurdejong/nss-pam-ldapd