Prevent crash

app/src/main/java/eu/faircode/email/EmailService.java

@@ -503,6 +503,7 @@ public class EmailService implements AutoCloseable {
 
                     boolean has4 = false;
                     boolean has6 = false;
+                    try {
                         Enumeration<NetworkInterface> interfaces = NetworkInterface.getNetworkInterfaces();
                         while (interfaces != null && interfaces.hasMoreElements()) {
                             NetworkInterface ni = interfaces.nextElement();
@@ -517,6 +518,14 @@ public class EmailService implements AutoCloseable {
                                         has6 = true;
                             }
                         }
+                    } catch (Throwable ex2) {
+                        Log.e(ex2);
+                        /*
+                            java.lang.NullPointerException: Attempt to read from field 'java.util.List java.net.NetworkInterface.childs' on a null object reference
+                                at java.net.NetworkInterface.getAll(NetworkInterface.java:498)
+                                at java.net.NetworkInterface.getNetworkInterfaces(NetworkInterface.java:398)
+                         */
+                    }
 
                     EntityLog.log(context, "Address main=" + main +
                             " count=" + iaddrs.length +