Fix Straight Talk T-mobile APN

Per CYAN-679, MMSC url is incorrect. Adjust accordingly

Change-Id: I9d9f76b4a35f8df44835ea68ff17f356d19c6f8a
diff --git a/prebuilt/common/etc/apns-conf.xml b/prebuilt/common/etc/apns-conf.xml
index e4666ed..566e3b4 100644
--- a/prebuilt/common/etc/apns-conf.xml
+++ b/prebuilt/common/etc/apns-conf.xml
@@ -569,7 +569,7 @@
   <apn carrier="T-Mobile US" mcc="310" mnc="260" apn="epc.tmobile.com" user="none" password="none" server="*" mmsc="http://mms.msg.eng.t-mobile.com/mms/wapenc" type="default,supl,mms" />
   <apn carrier="T-Mobile US LTE" mcc="310" mnc="260" apn="fast.t-mobile.com" user="none" password="none" server="*" mmsc="http://mms.msg.eng.t-mobile.com/mms/wapenc" type="default,supl,mms" />
   <apn carrier="Simple" mcc="310" mnc="260" apn="simple" mmsc="http://smpl.mms.msg.eng.t-mobile.com/mms/wapenc" type="default,supl,mms" />
-  <apn carrier="StraightTalk T-Mobile" mcc="310" mnc="260" apn="wap.tracfone" port="8080" mmsc="http://mmsc.tracfone.com" type="default,supl,mms" />
+  <apn carrier="StraightTalk T-Mobile" mcc="310" mnc="260" apn="wap.tracfone" port="8080" mmsc="http://mms.tracfone.com" type="default,supl,mms" />
   <apn carrier="T-Mobile US 270" mcc="310" mnc="270" apn="epc.tmobile.com" user="none" password="none" server="*" mmsc="http://mms.msg.eng.t-mobile.com/mms/wapenc" type="default,supl,mms" />
   <apn carrier="T-Mobile US 310" mcc="310" mnc="310" apn="epc.tmobile.com" user="none" password="none" server="*" mmsc="http://mms.msg.eng.t-mobile.com/mms/wapenc" type="default,supl,mms" />
   <apn carrier="Cingular 380 ATT" mcc="310" mnc="380" apn="proxy" proxy="wireless.cingular.com" port="80" mmsc="http://mmsc.cingular.com/" mmsproxy="wireless.cingular.com" type="default,supl,mms" />