Fix the SSL_set1_sigalgs() macro

This macro has a typo in it which makes it unusable. This issue was already
fixed in 1.0.2 in commit 75fdee04, but the same fix was not applied to
other branches.

Reviewed-by: Tim Hudson <tjh@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/2160)