Simplify the ChangeCipherSpec logic.

It's the same between TLS and SSL 3.0. There's also no need for the
do_change_cipher_spec wrapper (it no longer needs checks to ensure it
isn't called at a bad place). Finally fold the setup_key_block call into
change_cipher_spec.

Change-Id: I7917f48e1a322f5fbafcf1dfb8ad53f66565c314
Reviewed-on: https://boringssl-review.googlesource.com/6834
Reviewed-by: Adam Langley <alangley@gmail.com>
diff --git a/ssl/s3_clnt.c b/ssl/s3_clnt.c
index 0fca13c..7ff0a15 100644
--- a/ssl/s3_clnt.c
+++ b/ssl/s3_clnt.c
@@ -388,9 +388,7 @@
         }
         ssl->init_num = 0;
 
-        if (!ssl->enc_method->setup_key_block(ssl) ||
-            !ssl->enc_method->change_cipher_state(
-                ssl, SSL3_CHANGE_CIPHER_CLIENT_WRITE)) {
+        if (!tls1_change_cipher_state(ssl, SSL3_CHANGE_CIPHER_CLIENT_WRITE)) {
           ret = -1;
           goto end;
         }
@@ -486,7 +484,7 @@
           goto end;
         }
 
-        if (!ssl3_do_change_cipher_spec(ssl)) {
+        if (!tls1_change_cipher_state(ssl, SSL3_CHANGE_CIPHER_CLIENT_READ)) {
           ret = -1;
           goto end;
         }