Fix division by zero

CID 191124 (#1 of 1): Division or modulo by float zero (DIVIDE_BY_ZERO)
3. divide_by_zero: In expression 60. / (double)numberOfFiles, division by expression numberOfFiles which may be zero has undefined behavior.

CID 191125 (#1 of 1): Division or modulo by float zero (DIVIDE_BY_ZERO)
3. divide_by_zero: In expression 27. / (double)numberOfIndices, division by expression numberOfIndices which may be zero has undefined behavior.

Change-Id: If4f4a6795c1dfcae904ef7279ab25a1f855a6387
Reviewed-by: Karsten Heimrich <karsten.heimrich@qt.io>