Use SSL_CLIENT_USE_TLS1_2_CIPHERS instead of ssl3_version_from_wire.

The latter was only added after branch point.

Change-Id: I19970478ee301ad85c8f2fb2c76ebde26ebd9887
Reviewed-on: https://boringssl-review.googlesource.com/3250
Reviewed-by: Adam Langley <agl@google.com>

ssl/t1_lib.c

diff --git a/ssl/t1_lib.c b/ssl/t1_lib.c
index 39627eb..a579b36 100644
--- a/ssl/t1_lib.c
+++ b/ssl/t1_lib.c
@@ -954,7 +954,7 @@
     }
   }
 
-  if (ssl3_version_from_wire(s, s->client_version) >= TLS1_2_VERSION) {
+  if (SSL_CLIENT_USE_TLS1_2_CIPHERS(s)) {
     size_t salglen;
     const uint8_t *salg;
     salglen = tls12_get_psigalgs(s, &salg);