v1.41.1 x-goog-api-client header support; uploading bug fixes

Bug fixes:

• #1430 ResumableUpload modifies the existing HttpClient
• #1449 Improve error handling for closed streams when uploading
• #1453 Google.Apis 1.41.0 > "Names in version headers must be unique"

New features:

• #1440 Support x-goog-api-client in REST libraries