add option to jenkins::slave to support disableSslVerification

[neoice]

Java CA management is irritating, I'd like the option to just pass the swarm client -disableSslVerification.

[jlambert121]

@neoice is this something you could send a PR for that option? I don't run any slaves so I'm not able to do it.

[matthewbarr]

Do you use SSL, but just disable the verification? for the masterURL?

And if you can't do a PR, then the typical command line- do you need to use an options flag like JAVA_OPTIONS or something?

[neoice]

@jlambert121 I could probably write a pull request. I'll see if I get any time in the next few weeks to give it a go.

@matthewbarr JAVA_OPTIONS would probably meet my needs and be more generally useful. it's probably a better solution too because then it's possible to do a dumb thing like disable SSL verification, but it's not as easy or obvious.

[rtyler]

I believe this is covered with the merging of #122 which will be in the next release.