inverted comparison to avoid typecast errors

Forcing boolean to be cast to integer when comparing to column_value of IPAddr class (PostgreSQL inet column type) resulted in "undefined method `to_i' for false:FalseClass". Inverting the comparison from: column_value != false, to: false != column_value, forced the typecast to the way around.
Merge pull request #364 from forain/master

inverted comparison to avoid typecast errors