Allow some bacula::params::validate parameter values to be undef(ined)

[mjhennig]

Use undef as default value for bacula::params::validate parameters that are allowed to be (and even checked for being) undefined - rather than using an empty string (''), which seems to override any undefined parameters and thus causes validation to fail.

[rharrison10]

The main reason these were left as '' by default is the class that feeds the bacula::params::validate class already uses undef as the default. Basically the only way to actually have '' be the actual value to this class is only to call the class directly.

That said, you are right. If the calling class uses undef as the default its only reasonable that the child class use the same as a default. Give me a bit to look closer but I'm already inclined to accept this because, well, logical... :-)

[mjhennig]

Thank you! Note, however, that one may also consider leaving the empty string defaults but changing the conditional statements later on - as an alternative to this approach. Though I am not sure which way might be better.

[jyaworski]

I'm running into this now, with puppet 4.

Error: Could not retrieve catalog from remote server: Error 400 on SERVER: Evaluation Error: Error while evaluating a Function Call, "" is not an absolute path. at /etc/puppet/environments/production/modules/bacula/manifests/params/validate.pp:183:5 on node puppet1