Fix some callback type signatures. (#4227)

* Fix some callback type signatures.

SSL_CTX_set_psk_server_callback:
https://www.openssl.org/docs/man1.1.1/man3/SSL_CTX_set_psk_server_callback.html
https://github.com/openssl/openssl/blob/OpenSSL_1_0_2/ssl/ssl.h#L1355
https://github.com/openssl/openssl/blob/OpenSSL_1_1_0/include/openssl/ssl.h#L734

SSL_CTX_set_tlsext_servername_callback:
https://www.openssl.org/docs/man1.1.1/man3/SSL_CTX_set_tlsext_servername_callback.html
https://github.com/openssl/openssl/blob/OpenSSL_1_0_2/ssl/s3_lib.c#L3964
https://github.com/openssl/openssl/blob/OpenSSL_1_1_0/ssl/s3_lib.c#L3499

* Missed a spot
1 file changed