MDEV-23661: RocksDB produces "missing initializer for member" warnings

Add -Wno-missing-field-initializers for MyRocks and gcc version below 5.0

storage/rocksdb/CMakeLists.txt

@@ -54,6 +54,9 @@ IF(CMAKE_CXX_COMPILER_ID MATCHES "GNU")
     SKIP_ROCKSDB_PLUGIN("${OLD_COMPILER_MSG}")
   ENDIF()
   SET(CXX11_FLAGS "-std=c++11")
+  IF (GCC_VERSION VERSION_LESS 5.0)
+    SET(CXX11_FLAGS "-Wno-missing-field-initializers")
+  ENDIF()
 ELSEIF (CMAKE_CXX_COMPILER_ID MATCHES "Clang")
   IF ((CMAKE_CXX_COMPILER_VERSION AND CMAKE_CXX_COMPILER_VERSION VERSION_LESS  3.3) OR
      (CLANG_VERSION_STRING AND CLANG_VERSION_STRING VERSION_LESS  3.3))