Handle a memory allocation failure in ssl3_init_finished_mac()

The ssl3_init_finished_mac() function can fail, in which case we need to
propagate the error up through the stack.

RT#3198

Reviewed-by: Rich Salz <rsalz@openssl.org>
diff --git a/ssl/ssl_err.c b/ssl/ssl_err.c
index 377061b..0c46768 100644
--- a/ssl/ssl_err.c
+++ b/ssl/ssl_err.c
@@ -60,6 +60,7 @@
     {ERR_FUNC(SSL_F_SSL3_GENERATE_MASTER_SECRET),
      "ssl3_generate_master_secret"},
     {ERR_FUNC(SSL_F_SSL3_GET_RECORD), "ssl3_get_record"},
+    {ERR_FUNC(SSL_F_SSL3_INIT_FINISHED_MAC), "ssl3_init_finished_mac"},
     {ERR_FUNC(SSL_F_SSL3_OUTPUT_CERT_CHAIN), "ssl3_output_cert_chain"},
     {ERR_FUNC(SSL_F_SSL3_READ_BYTES), "ssl3_read_bytes"},
     {ERR_FUNC(SSL_F_SSL3_READ_N), "ssl3_read_n"},