Description of problem:

foreman-maintain's "Prepare backup Directory" check passes even when the backup directory doesn't exist

How reproducible:

• Always

Is this issue a regression from an earlier version:

• No

Steps to Reproduce:

1. Make sure "/tmp/test" doesn't exist
2. Run "foreman-maintain backup offline --preserve-directory /tmp/test"

Actual behavior:
"Prepare backup Directory" check passes and later the backup command fails on "Generate metadata" as the directory doesn't exist.

--------------------------------------------------------------------------------
Prepare backup Directory:                                             [OK]
--------------------------------------------------------------------------------
Generate metadata: 
\ Saving metadata to metadata.yml                                     [FAIL]    
No such file or directory @ rb_sysopen - /tmp/test/metadata.yml
--------------------------------------------------------------------------------
Scenario [Backup] failed. 

Expected behavior:
Fail "Prepare backup Directory" check if the backup directory doesn't exist 

Business Impact / Additional info:

• https://issues.redhat.com/browse/SAT-28126