Add the krb5/FreeIPA RADIUS companion daemon

This daemon listens for RADIUS packets on a well known
UNIX domain socket. When a packet is received, it queries
LDAP to see if the user is configured for RADIUS authentication.
If so, then the packet is forwarded to the 3rd party RADIUS server.
Otherwise, a bind is attempted against the LDAP server.

https://fedorahosted.org/freeipa/ticket/3366
http://freeipa.org/page/V3/OTP

daemons/ipa-otpd/ipa-otpd@.service.in

@@ -0,0 +1,9 @@
+[Unit]
+Description=ipa-otpd service
+
+[Service]
+EnvironmentFile=@sysconfdir@/ipa/default.conf
+ExecStart=@libexecdir@/ipa-otpd $ldap_uri
+StandardInput=socket
+StandardOutput=socket
+StandardError=syslog