Reset upload number to 1 for derivative ABI bumps

[Impact]

For derivative kernels we reset the upload number to 1 when bumping the ABI. For the meta packages we just continue to increment the upload number. This at best looks odd and at worst may result in some confusion.

Update the scripting in linux-meta to likewise reset the upload number whenever its derivative kernel has done an ABI bump.

[Test Case]

When preparing a derivative meta package, note that an ABI bump results in the upload number being reset to 1, while subsequent uploads using the same ABI result in incrementing the upload number.

[Where problems could occur]

This change affects only preparation of derivative meta packages. Bugs could result in having an unexpected upload number in the package version, but any such mistakes should be caught when reviewing package changes prior to upload.