Old monkeys don't get replace by new ones

[VakarisZ]

Describe the bug

In Hadoop exploiter(likely some others as well), old monkeys don't get overwritten by new ones.

To Reproduce

Steps to reproduce the behavior:

1. Run hadoop exploiter in zoo
2. Machines get exploited, but no new monkeys are uploaded, old ones are launched instead

Expected behavior

The monkey should either clean itself properly after a run or replace the binaries already present

OS's

Both

[mssalvatore]

This is likely the culprit:

[mssalvatore]