Fix breakage when ssl_cert/ssl_ca/ssl_key options are unset and the f…

[sigmunau]

…uture parser is in use

[ghost]

Jenkins standing by to test this. If you aren't a maintainer, you can ignore this comment. Someone with commit access, please review this and clear it for Jenkins to run; then say 'jenkins, test it'.

[ltutar]

After fixing the code as stated in this issue when I was trying to install two different software on the same machine, I get the error

Error: Could not retrieve catalog from remote server: Error 400 on SERVER: Evaluation Error: Error while evaluating a Function Call, Failed to parse inline template: undefined method `sort' for nil:NilClass at /etc/puppetlabs/code/environments/production/modules/logstashforwarder/manifests/config.pp:114:20 on node xldeployagent.home

See #67 for more information.
Solving this issue introduces new issues in my case. Just wanted to let you know.

[ghost]

Can one of the admins verify this patch?