We use underscores everywhere except these files, which use hyphens.
Switch them to be consistent.
Change-Id: I67eddbdae7caaf8405bdb4a0c1b65e6f3ca43916
Reviewed-on: https://boringssl-review.googlesource.com/c/boringssl/+/50808
Reviewed-by: Adam Langley <agl@google.com>
Commit-Queue: David Benjamin <davidben@google.com>