Suppress warnings about "already initialized constant"s in bundle update spec
Suppress warnings about "already initialized constant"s in bundle update spec

- Add `:suppress_stderr` option to `Spec::Helpers#bundle`
- Add third, optional `suppress_stderr` argument to `Spec::Helpers#sys_exec` to suppress stderr

mvz/bundler,dilumnavanjana/bundler,RochesterinNYC/bundler,dilumnavanjana/bundler,mpapis/bundler,bronzdoc/bundler,bundler/bundler,seanlinsley/bundler,seanlinsley/bundler,RochesterinNYC/bundler,mvz/bundler,mpapis/bundler,bundler/bundler,asutoshpalai/bundler,bronzdoc/bundler,asutoshpalai/bundler