When running a command which fails on a management worker the python Traceback error from the management worker is injected to the executions table together with the appropriate error.
We should use cfy events -e <execution id> to see the error itself and remove the 'error' column from 'cfy exec list'.
As for 'cfy exec get <execution id>', we should move the error from the 'error' column in the table, and put it externally similarly to "Execution Parameters".
Steps to reproduce:
1. cfy snapshot create
2. cfy snapshot restore <snapshot id>
3. wait a few seconds
4. cfy exec list
snapshot restore should fail since no -f flag was placed