qualify fd.fieldName in readParquetRowGroupsToTable

[rianoc-kx]

pq.readParquetRowGroupsToTable fails with 'fd.fieldName. Line 36 was missing the clib. prefix its four siblings have, and under KDB-X 5 the 5>.z.K branch that would otherwise make fd a global never runs.

q)arrow:use`kx.arrow
q)arrow.pq.readParquetRowGroupsToTable["t.parquet"; enlist 0i; 0 1i; (::)]
'fd.fieldName