Fixing ECDSA, support EdDSA signatures in CSRs.
* src/certreq.c (ksba_certreq_set_sig_val): Remove MSB handling of 0x80 for ECDSA, because it is done by GnuPG.
Distinguishing EdDSA signature in libgcrypt format, make a signature
simply concatinate r and s.
RFC 8410 specifies EdDSA signature is just concatination of R and S.
- Signed-off-by: NIIBE Yutaka <email@example.com>