removed sys.calls() as further follow up to #4244 and #4228 to pass dev-cran-lin
removed sys.calls() as further follow up to #4244 and #4228 to pass dev-cran-lin

Rdatatable/data.table,jangorecki/data.table,jangorecki/data.table,jangorecki/data.table,vlulla/data.table,vlulla/data.table,vlulla/data.table,Rdatatable/data.table,Rdatatable/data.table,Rdatatable/data.table,jangorecki/data.table,vlulla/data.table