func_odbc: NODATA if SQLNumResultCols returned 0 columns on readsql

The functions acf_odbc_read/cli_odbc_read ignore a number of columns
returned by the SQLNumResultCols.
If the number of columns is zero it means no data.
In this case, a SQLFetch function has to be not called,
because it will cause an error.

ASTERISK-27888 #close

Change-Id: Ie0f7bdac6c405aa5bbd38932c7b831f90729ee19