Modify APN for "Mobile TeleSystems" Belarus

IPv4v6 support was added to main APN "mts" for "Mobile TeleSystems" Belarus(mcc="257", mnc="02")

<apn carrier="MTS Belarus"
      mcc="257"
      mnc="02"
      apn="mts"
      user="mts"
      password="mts"
      protocol="IPV4V6"
      roaming_protocol="IPV4V6"
      authtype="1"
      type="default,supl"
/>

<apn carrier="MTS Belarus WAP"
     mcc="257"
     mnc="02"
     apn="mts"
     user="mts"
     password="mts"
     proxy="192.168.192.168"
     port="9201"
     authtype="1"
     type="default,supl"
 />

  <apn carrier="MTS Belarus MMS"
     mcc="257"
     mnc="02"
     apn="mts"
     user="mts"
     password="mts"
     mmsc="http://mmsc"
     mmsproxy="192.168.192.168"
     mmsport="9201"
     authtype="1"
     type="mms"
 />

Change-Id: Ifc8b7da989450b3d2f8c7f681965d90c3a56f800
diff --git a/etc/apns-full-conf.xml b/etc/apns-full-conf.xml
index 3697b4a..f1f9368 100644
--- a/etc/apns-full-conf.xml
+++ b/etc/apns-full-conf.xml
@@ -6269,6 +6269,8 @@
       apn="mts"
       user="mts"
       password="mts"
+      protocol="IPV4V6"
+      roaming_protocol="IPV4V6"
       authtype="1"
       type="default,supl"
   />