Fix always schedule renewal of security token

[vereecw]

Fix for issue #392

Link to reason in OPC-UA documentation in comment in the issue.

We've also taken a look at the C library for OPC-UA and found no check for MessageSecurityMode.

renewSecureChannel
function call 1
function call 2

[magiconair]

Hi @VereeckenWannes, I assume you've tested that on your setup. @kung-foo added that in #370 Maybe there was a specific reason.

[magiconair]

Lets merge this and see if this breaks things.

[kung-foo]

@magiconair honestly, 99% of my testing is against "secure" servers. I never did any lifetime/session testing against servers with a security mode of none.

IIRC I did have a patched version of a node-opcua-based server where I forced the session lifetime to something extremely short (i.e. 15 seconds). Maybe it's worth resurrecting something like that for the integration tests.

[vereecw]

@magiconair yes, we tested in on multiple setups and this change fixed our issue with losing our opcua connection after the lifetime expires when SecurityMode is set to none.

[magiconair]

@kung-foo that sounds like a good idea. @VereeckenWannes thank you.