FTP errors get silenced

[stikos]

This change causes FTP errors to get silenced and not propagated, resulting in jobs finishing in a COMPLETED stated, when in fact FTP operations may have failed.
Reverting this change fixes the issue, as it's been verified by creating a new filer image and testing it by running taskmaster with --localKubeConfig and an incorrect input file filename (according to this example)

Proof (better view with cat): bug_demo.txt