Fixed the syntax of QueryRaw as it didn't work

//When I try this 
var response = client.Search(func);

//This worked if the definition of func was
Func<SearchDescriptor<dynamic>, SearchDescriptor<dynamic>> func = s => s
               .AllTypes()
               .From(0)
               .Size(5)
               .QueryRaw(@"{""match_all"": {} }")
               ;

//This didn't work if the definition of func was
            Func<SearchDescriptor<dynamic>, SearchDescriptor<dynamic>> func = s => s
                .AllTypes()
                .From(0)
                .Size(10)
                .QueryRaw("\"match_all\" : { }")
);
Merge pull request #1077 from anshudutta/develop

Fixed the syntax of QueryRaw as it didn't work