Enable EMERGENCY mobile connections.

Hooks the ConnectivityManager.TYPE_MOBILE_EMERGENCY,
PhoneConstants.APN_TYPE_EMERGENCY, and NetworkCapabilities.NET_CAPABILITY_EIMS
together so carrier apps can request connections to this APN.

bug:21785357
Change-Id: I4786c02599658e65187e70966462c936a836a2c9
diff --git a/overlay/frameworks/base/core/res/res/values/config.xml b/overlay/frameworks/base/core/res/res/values/config.xml
index 517ce8a..5fcedcd 100644
--- a/overlay/frameworks/base/core/res/res/values/config.xml
+++ b/overlay/frameworks/base/core/res/res/values/config.xml
@@ -188,6 +188,7 @@
         <item>"mobile_ia,14,0,2,-1,true"</item>
         <item>"bluetooth,7,7,2,-1,true"</item>
         <item>"ethernet,9,9,9,-1,true"</item>
+        <item>"mobile_emergency,15,0,2,-1,true</item>
     </string-array>
 
     <!-- This string array should be overridden by the device to present a list of radio