MDEV-23539: aws key plugin - fails to build

Recent gcc/clang versions failed to compile the existing code.

Updating a later upstream SDK version was simple and required
only implementing a flush method. This was left blank as
there was no strong requirement to keep the error log
atomic or durable.

Reviewed-by: wlad@mariadb.com

The upstream SDK version added a flush method which was simple
to complete.

extra/aws_sdk/CMakeLists.txt

@@ -34,7 +34,7 @@ ENDFOREACH()
 IF(CMAKE_VERSION LESS "3.0")
   SET(GIT_TAG "1.0.8")
 ELSE()
-  SET(GIT_TAG "1.2.11")
+  SET(GIT_TAG "1.8.29")
 ENDIF()
 
 IF(MSVC_CRT_TYPE MATCHES "/MD")

plugin/aws_key_management/aws_key_management_plugin.cc

@@ -161,6 +161,10 @@ public:
   {
   }
 
+  virtual void Flush(void) override
+  {
+  }
+
 protected:
   virtual void ProcessFormattedStatement(Aws::String&& statement) override
   {