Remove a dead prototype.

Change-Id: I05cf52b31bd532505393e9a1ccae27f89f81f6f4
Reviewed-on: https://boringssl-review.googlesource.com/6680
Reviewed-by: Adam Langley <agl@google.com>

ssl/internal.h

diff --git a/ssl/internal.h b/ssl/internal.h
index 5832076..7910461 100644
--- a/ssl/internal.h
+++ b/ssl/internal.h
@@ -1164,9 +1164,6 @@
  * zero. */
 int tls1_check_ec_cert(SSL *s, X509 *x);
 
-int tls1_shared_list(SSL *s, const uint8_t *l1, size_t l1len, const uint8_t *l2,
-                     size_t l2len, int nmatch);
-
 /* ssl_add_clienthello_tlsext writes ClientHello extensions to |out|. It
  * returns one on success and zero on failure. The |header_len| argument is the
  * length of the ClientHello written so far and is used to compute the padding