Hammer CLI

When an image is created with user data false, listing that image using the hammer image list doesnt show anything under USER DATA column.

How Reproducible:
-------------------
Always

Steps:
-------------------
1. Create an image in GCE CR with user data set to false.
2. List all the images in GCE CR.

1. $ hammer compute-resource image list --compute-resource-id 1

Actual Behavior:
-------------------
The hammer image list shows blank for user-data image set to false.

---|---------------|------------------|---------------|---------------------|----------
ID | NAME | OPERATING SYSTEM | USERNAME | UUID | USER DATA
---|---------------|------------------|---------------|---------------------|----------
2 | gce_gceclloud | rhelcustom 7.6 | jitendracloud | 1238493266994992134 | true
1 | gceImage | rhelcustom 7.6 | jitendra | 4654324179607992309 |
---|---------------|------------------|---------------|---------------------|----------

Expected Behavior:
--------------------
Hammer listing image should show false for an image where user-data is false.