netdev-vport: Warn on IPsec tunnels when ovs-monitor-ipsec not running.
IPsec tunnels are only supported on Debian systems running
ovs-monitor-ipsec. Since that daemon configures IPsec, ovs-vswitchd
doesn't know whether IPsec will actually work. With this commit, a
warning is printed that it is unlikely to work unless that daemon is
started.
There is a more serious issue that IPsec traffic can pass unencrypted if
that daemon is not running. To fix that problem, changes to the kernel
module will need to occur. A future commit will address that issue, but
this earlier warning will be useful regardless.
Bug #4854