Fix failing syntax tests

[pasuder]

Due to RuboCop settings, usage of %w[] was not working correctly. That change fixes that.

Link to failed job: https://travis-ci.org/puppetlabs/puppetlabs-mysql/jobs/384698082

Offenses:
spec/functions/mysql_deepmerge_spec.rb:23:18: C: Style/WordArray: Use [] for an array of words. (https://github.com/bbatsov/ruby-style-guide#percent-w)
  index_values = %w[one two three]
                 ^^^^^^^^^^^^^^^^^
spec/functions/mysql_deepmerge_spec.rb:24:25: C: Style/WordArray: Use [] for an array of words. (https://github.com/bbatsov/ruby-style-guide#percent-w)
  expected_values_one = %w[1 2 2]
                        ^^^^^^^^^
spec/functions/mysql_deepmerge_spec.rb:62:22: C: Style/WordArray: Use [] for an array of words. (https://github.com/bbatsov/ruby-style-guide#percent-w)
  index_values_two = %w[key1 key2]
                     ^^^^^^^^^^^^^

Related to #1084

[david22swan]

@pasuder Rebase the PR and I will be happy to merge

[pmcmaw]

@pasuder thank you for taking your time to contribute. I can confirm that this issue was resolved in the following commit: c9a9419

Apologies and thank you for contributing. I plan on closing your PR and if you disagree feel free to reopen.

Many Thanks
Paula

[pasuder]

OK, great, thx.