(PDK-1167) Validator should honor case sensitive of the file system

[glennsarti]

Blocked on fb12b97 being merged

---

Previously the validator expected that any targets passed into the parse_targets
method were always case sensitive due to the way File.fnmatch matches file
names and paths. Due to the glob based searching, any paths returned from the
method will always represent what's on disk, as opposed to the originating
target path.

This commit updates the File.fnmatch method to instead base the matching on the
canonical directory name (from PDK::Util.canonical_path) which converts
case insensitive targets into their actual on-disk name.

This commit also adds a test for this scenario.

---

Previously the testing for the parse_targets method was being performed in
multiple places for no added test coverage. Also in order to test this method
required pervasive mocking of the file system which had many side effects. This
commit refactors the parse_targets testing:

• Any actual File and Dir methods used in parse_targets was refactored to the
  PDK::Util::FileSystem module, in order to make mocking less intrusive. In
  particular the mocking of .file?, .directory? and .glob? made it impossible
  to debug tests because tools like pry use these methods. Without this refactor
  it was impossible to debug tests.

  Note that "readonly" operations like File.join were not refactored as they are
  not mocked in tests and do not actually touch the host operating system,
  unlike glob, and file? etc.

• The tests for vase_validator were modified to mock the PDK:Util:FileSystem
  module, not the actual File and Dir classes.

• The puppet_syntax_spec.rb file used to test the .parse_targets method however
  this was unnecssary. The test for the .pattern_ignore property were moved
  from puppet_syntax_spec.rb into base_validator_spec.rb as this is what was
  actually being tested. puppet_syntax_spec.rb now just ensures that the
  pattern_ignore method is set correctly

• Both the it_accepts_metadata_json_targets and it_accepts_pp_targets helper
  files were testing functionality that was already being tested in the
  base_validator_spec.rb (Namely filtering on pattern). In this case the
  duplicate test is removed and instead we test that the pattern property is as
  we expect.

• Superfluous mocking of the File class was removed from any tests.

• Fixed a minor typo in the pattern for the puppet_syntax validator whereby the
  pattern should be '**/*.pp'

• All of the File and Dir mocking was removed from the name_spec.rb test file
  and instead we just mock the return from the parse_targets method of the base
  validator. The duplicate testing of the parse_targets method we not required
  and actually reflects what the test is testing for.

[coveralls]

Coverage decreased (-0.06%) to 93.011% when pulling 9f33c38 on glennsarti:pdk-1167-case-sensitive-paths into 1ee825e on puppetlabs:master.