VPN: delete the "abort" file before starting VPN daemons.

Bug: 5714296
Change-Id: Idba41b9f3907747a84387ea4f3e930b3a185a06e
diff --git a/services/java/com/android/server/connectivity/Vpn.java b/services/java/com/android/server/connectivity/Vpn.java
index 55e0678..72cf512 100644
--- a/services/java/com/android/server/connectivity/Vpn.java
+++ b/services/java/com/android/server/connectivity/Vpn.java
@@ -482,6 +482,7 @@
                 if (state.exists()) {
                     throw new IllegalStateException("Cannot delete the state");
                 }
+                new File("/data/misc/vpn/abort").delete();
 
                 // Check if we need to restart any of the daemons.
                 boolean restart = false;