Fix SearchContext occasionally closed prematurely

[jaymode]

PR for #5165

[s1monw]

given this I think we should add some checks to the place where this is created in SearchService
ie. this:

 SearchContext createAndPutContext(ShardSearchRequest request) throws ElasticsearchException {
        SearchContext context = createContext(request);
        activeContexts.put(context.id(), context);
        context.indexShard().searchService().onNewContext(context);
        return context;
    }

should look like:

 SearchContext createAndPutContext(ShardSearchRequest request) throws ElasticsearchException {
        SearchContext context = createContext(request);
        boolean success = false;
        try {
            activeContexts.put(context.id(), context);
            context.indexShard().searchService().onNewContext(context);
            success = true;
            return context;
        } finally {
              if (!success) { 
                 freeContext(context);
              }
        }
    }

[s1monw]

I left one comment but in general this looks great... Can you maybe change the commit message to follow this pattern:

Short description (80 chars max)

Long description over multiple lines (80 Chars per line)

Closes #5165

thanks so much!

[jaymode]

@s1monw just updated per your comments regarding the SearchService and the commit message

[s1monw]

looks good I will try merging this in tomorrow!

[s1monw]

pushed thanks so much