fixing return type of Zencode_@1_@2(): "int" -> "@2"
fixing return type of Zencode_@1_@2(): "int" -> "@2"

Zencode_@1_@2() is supposed to return a value of type "@2",
e.g., "oid" in the current case, not a value of type "int".

Thanks go to the Microsoft compiler on Windows for reporting
MonetDB5\src\modules\mal\zorder.mx(96) : warning C4267: "return" : conversion from "size_t" to "int", possible loss of data

zyzyis/monetdb,zyzyis/monetdb,zyzyis/monetdb,zyzyis/monetdb,zyzyis/monetdb,zyzyis/monetdb,zyzyis/monetdb,zyzyis/monetdb,zyzyis/monetdb,zyzyis/monetdb