Fix count_all_results on SQLSRV with query cache

[addbee]

Fix for count_all_results on MSSQL when using start_cache

• usage scenario, pagination

[narfbg]

Explain what's broken please.

[addbee]

Using MSSQL / SQLSRV Driver with SQL Azure

Previously:
When using start_cache() with a query having an order_by() clause, and then performing count_all_results() this resulted in an SQL error (MSSQL specific, due to the order by in a count(*))

This is worked around for regular queries with the qb_orderby being overridden in count_all_results but the compile select uses the qb_cache_orderby when cache is enabled

After the change:
qb_cache_orderby is emptied while the count is performed, then reinstated.

[narfbg]

Hope you don't mind me hacking the fix myself ... I wanted to simplify the code.

Also, your patch isn't following our styleguide - please read it if you ever want to contribute again.

[narfbg]

Well, as evident by #5282, both of our patches are erroneous.

While it is my fault that I didn't test mine, yours should've never been submitted if you haven't solved your own problem with it ... please don't do that again.