BUG/MINOR: ssl: copy curves, sigalgs and client_sigalgs in srv_ssl_settings_cpy()

BUG/MINOR: ssl: copy curves, sigalgs and client_sigalgs in srv_ssl_settings_cpy()

When a server inherits SSL settings from default-server, the curves,
sigalgs and client_sigalgs fields were not copied despite being
allocated by ssl-default-server-* keywords. This causes use-after-free
when the original ssl_ctx is destroyed while another reference still
holds the pointer.

Add strdup() calls guarded by the same OpenSSL API version checks
used elsewhere in the copy function.

Fixes issue #3506.

This change is should be backported to all supported branches.