Pull request #823: CAS-14362 : check that each element of datapath exists before using it in os.path.samefile to check to see if it's the same as measurespath
Merge in CASA/casa6 from CAS-14362 to release/6.6.4
* commit '3581bd6c52f7dbb411721f83553d9520eed02739': CAS-14362 : check that each element of datapath exists before using it in os.path.samefile to check to see if it's the same as measurespath