Enhance the perform_rehome_operation() function to validate the subcloud
availability status before running the 'dcmanager subcloud manage' command.
This ensures that the subcloud is online before management is attempted,
preventing failures when the subcloud is offline or unreachable.
Test Plan:
PASS: Validate subcloud availability status before managing subcloud
PASS: Perform manage subcloud only if it is online.
Change-Id: I730bb321b93f59c13b53554b79d18e24d62a8f15
Signed-off-by: aabhinav <ayyapasetti.abhinav@windriver.com>
8a82a46977