Rename ssl_locl.h to internal.h

Match the other internal headers.

Change-Id: Iff7e2dd06a1a7bf993053d0464cc15638ace3aaa
Reviewed-on: https://boringssl-review.googlesource.com/4280
Reviewed-by: Adam Langley <agl@google.com>
diff --git a/ssl/ssl_ciph.c b/ssl/ssl_ciph.c
index 1253f8f..4df8a7b 100644
--- a/ssl/ssl_ciph.c
+++ b/ssl/ssl_ciph.c
@@ -147,7 +147,7 @@
 #include <openssl/obj.h>
 #include <openssl/sha.h>
 
-#include "ssl_locl.h"
+#include "internal.h"
 
 
 struct handshake_digest {