system/security: sync with latest BoringSSL.

This change allows system/security to build with the latest BoringSSL.

1) RSA methods have gained a function pointer, |supports_digest|, which
   allows methods to indicate that they only support certain hash
   functions via the high-level interface.

2) EC_GROUP_set_point_conversion_form has been removed (it was
   previously a no-op).

Change-Id: I590094d8904f418cfd6baf064ac9799525fbc09e
diff --git a/keystore-engine/android_engine.cpp b/keystore-engine/android_engine.cpp
index ee16312..b368a3f 100644
--- a/keystore-engine/android_engine.cpp
+++ b/keystore-engine/android_engine.cpp
@@ -220,6 +220,7 @@
   RSA_FLAG_CACHE_PUBLIC | RSA_FLAG_OPAQUE | RSA_FLAG_EXT_PKEY,
 
   NULL /* keygen */,
+  NULL /* supports_digest */,
 };
 
 const char* ecdsa_get_key_id(const EC_KEY* ec_key) {