[Serusers] Add Attribute to Access-Request in SER.

[Miguel Angel Villar]

Hi list.
	I'm using RADIUS to authenticate user REGISTER on SER with nice
results. When SER receives a REGISTER message it generates an Access-Request
to RADIUS server (RADIATOR), the Access-Request message received in RADIATOR
is like:

Code:       Access-Request
Identifier: 168
Authentic:  <161>7<191><14>t<20><162><161>b<182><151><127><241><237><197>G
Attributes:
        User-Name = "someuserser at sip.someitsp.net"
        Digest-Attributes = "<10><12>someuser"
        Digest-Attributes = "<1><20>sip.someitsp.net"
        Digest-Attributes = "<2>*4225fe505c23a2fcef5689ac36fb5aa31fc85"
        Digest-Attributes = "<4>&sip:111200 at sip.someitsp.net"
        Digest-Attributes = "<3><10>REGISTER"
        Digest-Attributes = "<5><6>auth"
        Digest-Attributes = "<9><10>00000926"
        Digest-Attributes = "<8><10>24a753fd"
        Digest-Response = "8626e3398aa04671f3454403fd34c55a"
        Service-Type = Sip-Session
        Sip-Uri-User = "111200"
        NAS-IP-Address = 10.10.10.10
        NAS-Port = 5060

	For logging purposes it would very usefull for me to have the IP
address of SIP UA as an attribute in Access-Request. I know that SER can get
that info from REGISTER message, the question is if SER (v0.8.14-3) is able
to insert that info as an attribute on Access-Request, or Can other version
do that?

THX!.
Miguel.-