tests: Cope with broken Libgcrypt versions
* common/t-sexputil.c (test_ecc_uncompress): Ignore unknwon curve errors.
For unknown reasons some versions of Fedora or RHEL provide a patched
version of Libgcrypt with Brainpool support removed. We better ignore
this error because it is a regression in 2.2.28 although that older
versions could not used Brainpool keys.
- GnuPG-bug-id: T5502
- Signed-off-by: Werner Koch <email@example.com>