racoon: Check the return value of setuid(2).

'racoon' was not checking the return value of setuid(2). This is a
security bug, though mitigated by SELinux. This bug would be exploited
by creating enough processes running as user 'vpn' that the setuid(2)
call fails with EAGAIN, so that the racoon process then continues
running as root.

Bug: 33938230
Test: Builds, 'racoon' starts correctly.
Change-Id: I916123c7de220c659fbe98bc2016f9f52002d2eb
1 file changed