Fix gem build including bin/bin/setup

[agrare]

adam@workstation:~/src/manageiq/ffi-vix_disk_lib$ gem build
WARNING:  See https://guides.rubygems.org/specification-reference/ for help
ERROR:  While executing gem ... (Gem::InvalidSpecificationException)
    ["bin/bin/setup"] are not files
	/usr/lib/ruby/vendor_ruby/rubygems/specification_policy.rb:500:in `error'
	/usr/lib/ruby/vendor_ruby/rubygems/specification_policy.rb:303:in `validate_non_files'
	/usr/lib/ruby/vendor_ruby/rubygems/specification_policy.rb:75:in `validate_required!'
	/usr/lib/ruby/vendor_ruby/rubygems/specification_policy.rb:46:in `validate'
	/usr/lib/ruby/vendor_ruby/rubygems/specification.rb:2647:in `validate'
	/usr/lib/ruby/vendor_ruby/rubygems/package.rb:299:in `build'
	/usr/lib/ruby/vendor_ruby/rubygems/package.rb:137:in `build'
	/usr/lib/ruby/vendor_ruby/rubygems/commands/build_command.rb:103:in `build_package'
	/usr/lib/ruby/vendor_ruby/rubygems/commands/build_command.rb:93:in `build_gem'
	/usr/lib/ruby/vendor_ruby/rubygems/commands/build_command.rb:73:in `execute'
	/usr/lib/ruby/vendor_ruby/rubygems/command.rb:328:in `invoke_with_build_args'
	/usr/lib/ruby/vendor_ruby/rubygems/command_manager.rb:253:in `invoke_command'
	/usr/lib/ruby/vendor_ruby/rubygems/command_manager.rb:193:in `process_args'
	/usr/lib/ruby/vendor_ruby/rubygems/command_manager.rb:151:in `run'
	/usr/lib/ruby/vendor_ruby/rubygems/gem_runner.rb:52:in `run'
	/usr/bin/gem:12:in `<main>'

With these changes this is the content of spec.files: LICENSE.txt, README.md, lib/ffi-vix_disk_lib.rb, lib/ffi-vix_disk_lib/api.rb, lib/ffi-vix_disk_lib/api_wrapper.rb, lib/ffi-vix_disk_lib/const.rb, lib/ffi-vix_disk_lib/disk_info.rb, lib/ffi-vix_disk_lib/enum.rb, lib/ffi-vix_disk_lib/exceptions.rb, lib/ffi-vix_disk_lib/libc.rb, lib/ffi-vix_disk_lib/safe_connect_params.rb, lib/ffi-vix_disk_lib/safe_create_params.rb, lib/ffi-vix_disk_lib/struct.rb, lib/ffi-vix_disk_lib/version.rb

And gem build is success

$ gem build
WARNING:  description and summary are identical
WARNING:  open-ended dependency on ffi (>= 0) is not recommended
  use a bounded requirement, such as '~> x.y'
WARNING:  open-ended dependency on bundler (>= 0, development) is not recommended
  use a bounded requirement, such as '~> x.y'
WARNING:  open-ended dependency on manageiq-style (>= 0, development) is not recommended
  use a bounded requirement, such as '~> x.y'
WARNING:  open-ended dependency on rake (>= 0, development) is not recommended
  use a bounded requirement, such as '~> x.y'
WARNING:  open-ended dependency on rspec (>= 0, development) is not recommended
  use a bounded requirement, such as '~> x.y'
WARNING:  open-ended dependency on simplecov (>= 0.21.2, development) is not recommended
  if simplecov is semantically versioned, use:
    add_development_dependency 'simplecov', '~> 0.21', '>= 0.21.2'
WARNING:  See https://guides.rubygems.org/specification-reference/ for help
  Successfully built RubyGem
  Name: ffi-vix_disk_lib
  Version: 1.3.1
  File: ffi-vix_disk_lib-1.3.1.gem

[agrare]

I don't think we actually wanted to include bin/setup in the published gem so I just left this out

# ls /opt/manageiq/manageiq-gemset/gems/ffi-vix_disk_lib-1.3.1/bin/
setup