Add no-op function ENGINE_register_all_complete.

libssh2 expects this function.

Change-Id: Ie2d6ceb25d1b633e1363e82f8a6c187b75a4319f
Reviewed-on: https://boringssl-review.googlesource.com/8735
Reviewed-by: David Benjamin <davidben@google.com>
diff --git a/crypto/crypto.c b/crypto/crypto.c
index c9f2bc8..2443126 100644
--- a/crypto/crypto.c
+++ b/crypto/crypto.c
@@ -153,6 +153,10 @@
 
 void ENGINE_load_builtin_engines(void) {}
 
+int ENGINE_register_all_complete(void) {
+  return 1;
+}
+
 void OPENSSL_load_builtin_modules(void) {}
 
 int FIPS_mode(void) { return 0; }