Improve check_patches before applying

[jaumef]

When applying with "--from-commit" option, instead of using the ".patch" files uploaded, it uses all the patches on the "patch/<pr_number>" path.

This generates 2 problems:

• Slow check for all files (sorted by commit number) to find which one has the correct hash
• May apply more commits than uploaded
  • Patches made manually that are sorted under the ones uploaded
  • Copies of the patch files
  • A commit that was uploaded and then removed with a "push --force"
  • ...