Fix docs using cdap-cli.sh execute

`'`, `"`, `(`, and `)` are special characters in bash. We need to escape them so we can pass it to cdap-cli.sh.
don't need to escape the single-quotes when they are in a string. This works:
```
 $ <path-to-CDAP-SDK>/bin/cdap-cli.sh execute "\"SELECT * FROM cdap_user_pageviewstore WHERE key = '255.255.255.249'\""
```