[c++] Fix memory ordering semantics with close of Image.
[c++] Fix memory ordering semantics with close of Image.

mikeb01/Aeron,EvilMcJerkface/Aeron,mikeb01/Aeron,EvilMcJerkface/Aeron,mikeb01/Aeron,mikeb01/Aeron,EvilMcJerkface/Aeron,real-logic/Aeron,real-logic/Aeron,galderz/Aeron,real-logic/Aeron,real-logic/Aeron,galderz/Aeron,galderz/Aeron,EvilMcJerkface/Aeron,galderz/Aeron