Match generate_module naming conventions to their help text

[mkarlesky]

Summary

auto/generate_module.rb had three bugs:

• bumpy and camel were reversed. bumpy produced madScience and camel produced MadScience, the opposite of the script's own help text (bumpy - BumpyCaseFilenames, camel - camelCaseFilenames). See Module Generator naming conventions 'bumpy' and 'camel' are reversed. Ceedling#518 and In generate_module.rb 'bumpy' and 'camel' naming conventions are exchanged. #523.
• A naming convention given as a symbol was ignored. YAML configuration such as :naming: :snake supplies one, and file names silently kept their typed case.
• The svn add success check read $!, the last exception, rather than $?, the child process status. A successful add could therefore raise NoMethodError.

Testing

test/spec/generate_module_naming_spec.rb covers each convention, symbol input, and no convention. It failed before the fix and passes after it.

One existing example, generate_module_existing_file_spec.rb "with mch pattern fails when all files exist", expects meh_model where the generator produces meh_Model. It fails the same way on master without this change, so this PR leaves it alone.

Downstream note

Ceedling's Module Generator plugin currently swaps bumpy and camel before calling this script to work around the reversal (ThrowTheSwitch/Ceedling#1338). When Ceedling's Unity submodule picks up this fix, that mapping must be removed in the same change, or the names will reverse again.