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: Id92a5e28d19407cc7a8f8b5478b23457f2f7f89d
diff --git a/core/java/android/net/NetworkCapabilities.java b/core/java/android/net/NetworkCapabilities.java
index 658051c..514d24a 100644
--- a/core/java/android/net/NetworkCapabilities.java
+++ b/core/java/android/net/NetworkCapabilities.java
@@ -133,7 +133,8 @@
 
     /**
      * Indicates this is a network that has the ability to reach a carrier's
-     * Emergency IMS servers, used for network signaling during emergency calls.
+     * Emergency IMS servers or other services, used for network signaling
+     * during emergency calls.
      */
     public static final int NET_CAPABILITY_EIMS           = 10;