Modulo operation does not respect null values

[Veranika Liaukevich]

Modulo division interprets nulls as regular values.
Definition of the collection:

typedef marray <char, 2> NullValueArrayTest;
typedef set <NullValueArrayTest> null values [5:7] NullValueSetTest;

Values (the third value is null):

$ rasql  -q 'select csv(x) from values as x' --out string --quiet
{1},{2},{5}

Modulo operation:

$ rasql  -q 'select csv( mod(x, 2) ) from values as x' --out string --quiet
{1},{0},{1}

The correct output should be:

{1}, {0}, {5} 

[Dimitar Misev]

Patch submitted.