- gnutls.keyring: Nikos key refreshed to be unexpired

- GnuTLS 3.6.2:
* libgnutls: When verifying against a self signed certificate ignore issuer.
That is, ignore issuer when checking the issuer's parameters strength,
resolving issue #347 which caused self signed certificates to be
additionally marked as of insufficient security level.
* libgnutls: Corrected MTU calculation for the CBC ciphersuites. The data
MTU calculation now, it correctly accounts for the fixed overhead due to
padding (as 1 byte), while at the same time considers the rest of the
padding as part of data MTU.
* libgnutls: Address issue of loading of all PKCS#11 modules on startup
on systems with a PKCS#11 trust store (as opposed to a file trust store).
Introduced a multi-stage initialization which loads the trust modules, and
other modules are deferred for the first pure PKCS#11 request.
* libgnutls: The SRP authentication will reject any parameters outside
RFC5054. This protects any client from potential MitM due to insecure
parameters. That also brings SRP in par with the RFC7919 changes to
Diffie-Hellman.
* libgnutls: Added the 8192-bit parameters of SRP to the accepted parameters
for SRP authentication.
* libgnutls: Addressed issue in the accelerated code affecting
interoperability with versions of nettle >= 3.4.
* libgnutls: Addressed issue in the AES-GCM acceleration under aarch64.
* libgnutls: Addressed issue in the AES-CBC acceleration under ssse3 (patch by
Vitezslav Cizek).
* srptool: the --create-conf option no longer includes 1024-bit parameters.
* p11tool: Fixed the deletion of objects in batch mode.
- Dropped gnutls-check_aes_keysize.patch as it is included upstream now.