Move ex_data functions in ssl.h to a section.

Change-Id: Ie3b7c1956cc9d62091f649d0e621d84fce1d26ec
Reviewed-on: https://boringssl-review.googlesource.com/5879
Reviewed-by: Adam Langley <agl@google.com>
diff --git a/ssl/ssl_session.c b/ssl/ssl_session.c
index d08b682..926b387 100644
--- a/ssl/ssl_session.c
+++ b/ssl/ssl_session.c
@@ -184,12 +184,12 @@
   return index;
 }
 
-int SSL_SESSION_set_ex_data(SSL_SESSION *s, int idx, void *arg) {
-  return CRYPTO_set_ex_data(&s->ex_data, idx, arg);
+int SSL_SESSION_set_ex_data(SSL_SESSION *session, int idx, void *arg) {
+  return CRYPTO_set_ex_data(&session->ex_data, idx, arg);
 }
 
-void *SSL_SESSION_get_ex_data(const SSL_SESSION *s, int idx) {
-  return CRYPTO_get_ex_data(&s->ex_data, idx);
+void *SSL_SESSION_get_ex_data(const SSL_SESSION *session, int idx) {
+  return CRYPTO_get_ex_data(&session->ex_data, idx);
 }
 
 SSL_SESSION *SSL_SESSION_new(void) {