apn: Fixup legacy 'read_only' attribute

Replace with 'user_editable="false"', because 'read_only' hasn't been
around anymore for a long time.

Networks:
* 234,30 and 234,38 - Virgin UK
* 730,03 - Claro

Issue: FP3-A11#360
Change-Id: I21bc57c7f9e3cee9bd87125527d15913dd69c091
diff --git a/apns-conf.xml b/apns-conf.xml
index d418c7b..ceb2e8b 100644
--- a/apns-conf.xml
+++ b/apns-conf.xml
@@ -3011,8 +3011,7 @@
       mmsproxy="193.030.166.002"
       mmsport="8080"
       type="default,supl,mms"
-      user_editable="0"
-      read_only="true"
+      user_editable="false"
   />
   <apn carrier="EE Internet"
       mcc="234"
@@ -3186,8 +3185,7 @@
       mmsproxy="193.030.166.002"
       mmsport="8080"
       type="default,supl,mms"
-      user_editable="0"
-      read_only="true"
+      user_editable="false"
   />
   <apn carrier="Jersey Telecom"
       mcc="234"
@@ -29817,8 +29815,8 @@
       user="clarochile"
       password="clarochile"
       authtype="3"
-      read_only ="true"
       type="default,supl,dun"
+      user_editable="false"
   />
   <apn carrier="MMS Claro"
       mcc="730"
@@ -29830,8 +29828,8 @@
       mmsport="8080"
       mmsc="http://mms.clarochile.cl"
       authtype="1"
-      read_only ="true"
       type="mms"
+      user_editable="false"
   />
   <apn carrier="WAP Claro"
       mcc="730"