Add some ASN1_TIME related functions for the relevant PyOpenSSL patch.

[moriyoshi]

This patch adds the signatures for the following functions:

• ASN1_TIME_set_string
• ASN1_TIME_check

These are necssary in the PyOpenSSL patch which will be submitted shortly.

[mention-bot]

@moriyoshi, thanks for your PR! By analyzing the history of the files in this pull request, we identified @reaperhulk, @alex and @public to be potential reviewers.

[moriyoshi]

The PyOpenSSL patch is here: pyca/pyopenssl#612

[alex]

Jenkins, ok to test.

[alex]

Looks like there are some signature changes in OpenSSL across the versions; you may need to move some of the declerations to the macros section to avoid checking the constness.

[moriyoshi]

Yes, totally right. The constness of the argument for ASN1_TIME_check was changed at openssl/openssl@359b0c9. I moved it to MACRO.

[reaperhulk]

Thanks for your contribution!