fix merge nil hashes

[thde]

Apparently it can be the case that one of the hashes is nil. I added a nil check in the merge function.

Error: /Stage[main]/xxx::Config/Concat[/etc/file/config.yml]/Concat_file[/etc/file/config.yml]: Failed to generate additional resources us
ing 'eval_generate': undefined method `empty?' for nil:NilClass
/opt/puppetlabs/puppet/cache/lib/puppet/type/concat_file.rb:266:in `nested_merge'
/opt/puppetlabs/puppet/cache/lib/puppet/type/concat_file.rb:232:in `block in should_content'
/opt/puppetlabs/puppet/cache/lib/puppet/type/concat_file.rb:231:in `each'
/opt/puppetlabs/puppet/cache/lib/puppet/type/concat_file.rb:231:in `reduce'
/opt/puppetlabs/puppet/cache/lib/puppet/type/concat_file.rb:231:in `should_content'
/opt/puppetlabs/puppet/cache/lib/puppet/type/concat_file.rb:355:in `eval_generate'

[CLAassistant]

All committers have signed the CLA.

[puppet-community-rangefinder]

concat_file is a type

Breaking changes to this file WILL impact these 1 modules (exact match):

• saz-ssh

Breaking changes to this file MAY impact these 2 modules (near match):

• puppet3-concat
• puppetlabs-concat

This module is declared in 170 of 576 indexed public Puppetfiles.

---

These results were generated with Rangefinder, a tool that helps predict the downstream impact of breaking changes to elements used in Puppet modules. You can run this on the command line to get a full report.

Exact matches are those that we can positively identify via namespace and the declaring modules' metadata. Non-namespaced items, such as Puppet 3.x functions, will always be reported as near matches only.

[adrianiurca]

Hey @thde, thank you for your contribution!

kind regards,
@adrianiurca