Rename load_module_metadata test path

`rake spec` only finds test files that end in _spec.rb, so this test
was not being run. Correct the path name so that the test runs
properly.

diff --git a/spec/functions/load_module_metadata.rb b/spec/functions/load_module_metadata_spec.rb
similarity index 100%
rename from spec/functions/load_module_metadata.rb
rename to spec/functions/load_module_metadata_spec.rb