Fixes for #2162. SphinxQL: COUNT(*) get error.

When trying to get the total number of items, an error is returned.
For example, this query returns an error:
```sql
SELECT COUNT (*) FROM some_index WHERE MATCH ('foo');
```

![error](https://f.cloud.github.com/assets/3135712/2007226/f55f6370-8733-11e3-9474-12cdc1dc1224.png)

There are two ways to resolve:
1) Add ```GROUP BY```.

 
```sql
SELECT COUNT(*) AS cnt, 1 AS q FROM some_index WHERE MATCH ('foo') GROUP BY q;
```
![Add GROUP BY](https://f.cloud.github.com/assets/3135712/2007230/18ea62f4-8734-11e3-901b-befab4e72164.png)

2) use ```SHOW META```


```sql
SELECT * FROM some_index  WHERE MATCH ('foo') limit 0;
SHOW META;
```
![use SHOW META](https://f.cloud.github.com/assets/3135712/2007239/2a88ff34-8734-11e3-9abc-49d788c88359.png)

in the statistics table will be field ***total_found***
http://sphinxsearch.com/forum/view.html?id=10212

This pull request must be connected with this: #2162 

**Update**: attached screenshots.