Remove SSL_set_fallback_version.

Ding-dong the fallback's dead.
https://mailarchive.ietf.org/arch/msg/tls/xfCh7D7hISFs5x-eA0xHwksoLrc

Also we'll need to tweak the versioning code slightly to implement
supported_versions and it's nice to have this out of the way.

Change-Id: I0961e19ea56b4afd828f6f48858ac6310129503d
Reviewed-on: https://boringssl-review.googlesource.com/11120
Reviewed-by: David Benjamin <davidben@google.com>
Commit-Queue: David Benjamin <davidben@google.com>
CQ-Verified: CQ bot account: commit-bot@chromium.org <commit-bot@chromium.org>
diff --git a/ssl/internal.h b/ssl/internal.h
index c090094..0bc0b8e 100644
--- a/ssl/internal.h
+++ b/ssl/internal.h
@@ -1505,21 +1505,10 @@
  * |version|. */
 const SSL3_ENC_METHOD *ssl3_get_enc_method(uint16_t version);
 
-/* ssl_get_full_version_range sets |*out_min_version|, |*out_fallback_version|,
- * and |*out_max_version| to the minimum, fallback, and maximum enabled protocol
- * versions, respectively. The fallback version is the effective maximium
- * version used throughout the stack and the maximum version is the true maximum
- * for downgrade purposes. */
-int ssl_get_full_version_range(const SSL *ssl, uint16_t *out_min_version,
-                               uint16_t *out_fallback_version,
-                               uint16_t *out_max_version);
-
-/* ssl_get_version_range sets |*out_min_version| and
- * |*out_effective_max_version| to the minimum and maximum enabled protocol
- * versions, respectively. Note that, if there is a fallback version set, it
- * returns it as the maximum version. */
+/* ssl_get_version_range sets |*out_min_version| and |*out_max_version| to the
+ * minimum and maximum enabled protocol versions, respectively. */
 int ssl_get_version_range(const SSL *ssl, uint16_t *out_min_version,
-                          uint16_t *out_effective_max_version);
+                          uint16_t *out_max_version);
 
 /* ssl3_protocol_version returns |ssl|'s protocol version. It is an error to
  * call this function before the version is determined. */