- kadmin.service,krb5kdc.service: remove optional use of $KRB5REALM in command
  lines, because systemd parsing doesn't handle alternate value shell variable
  syntax
- kprop.service: add missing Type=forking so that systemd doesn't assume simple
- kprop.service: expect the ACL configuration to be there, not absent

- when starting the KDC or kadmind, if KRB5REALM is set via the
    /etc/sysconfig file for the service, pass it as an argument for the -r
    flag

- v1.4 kadmin client requires a v1.4 kadmind on the server, or use the "-O"
    flag to specify that it should communicate with the server using the
    older protocol
- new libkrb5support library
- v5passwdd and kadmind4 are gone
- versioned symbols
- pick up $KRB5KDC_ARGS from /etc/sysconfig/krb5kdc, if it exists, and pass
    it on to krb5kdc
- pick up $KADMIND_ARGS from /etc/sysconfig/kadmin, if it exists, and pass
    it on to kadmind
- pick up $KRB524D_ARGS from /etc/sysconfig/krb524, if it exists, and pass
    it on to krb524d *instead of* "-m"
- set "forwardable" in [libdefaults] in the default krb5.conf to match the
    default setting which we supply for pam_krb5
- set a default of 24h for "ticket_lifetime" in [libdefaults], reflecting
    the compiled-in default