Send VPN manager event when there is a network error

Bug: 191413541
Test: atest FrameworksNetTests:VpnTest
Change-Id: I767e23750ccf12c0c787a3ec23d4a520dc5bb570
(cherry picked from commit 64eaff5dba207a05ff9b1f9826de98ee05533b30)
Merged-In: I767e23750ccf12c0c787a3ec23d4a520dc5bb570
1 file changed