Fix Windows build.

Now that 11c0f8e54cfc68d7d8efe34d10ad58ded687fcfa has landed, none of
the cases of the switch in |ssl3_ctrl| ever break and so the “return 1”
at the end of the function is unreachable. MSVC is unhappy about that.

Change-Id: I001dc63831ba60d93b622ac095297e2febc5f078
diff --git a/ssl/s3_lib.c b/ssl/s3_lib.c
index 877f88d..7acbd23 100644
--- a/ssl/s3_lib.c
+++ b/ssl/s3_lib.c
@@ -467,8 +467,6 @@
     default:
       return 0;
   }
-
-  return 1;
 }
 
 int SSL_CTX_set_tlsext_servername_callback(