Use "manual" image modification method for OVB jobs

There is some yet to be determined issue when using libguestfs to modify
the images that is causing it to take up to 50 minutes. We can not
afford that much overhead in the OVB jobs. Instead, we use the manual
method of converting the image to raw and mounting it to do
modifications.

Closes-Bug: 1694280

Change-Id: I64c0aba5b047ea799991deaf89180f76a636f0fc
Depends-On: Ice4487aa8d263aa7f4a426b7924104a469bd1b52

scripts/quickstart/ovb-settings.yml

@@ -33,8 +33,7 @@ images_working_dir: "{{ working_dir }}"
 build_image_isolated: false
 build_undercloud: false
 images_destroy_working_dir: false
-modify_image_extract_list:
-  - /tmp/builder.log
+libguestfs_mode: false
 
 # Network settings
 step_adjust_mtu: true

toci-quickstart/config/testenv/ovb.yml

@@ -27,8 +27,7 @@ images_working_dir: "{{ working_dir }}"
 build_image_isolated: false
 build_undercloud: false
 images_destroy_working_dir: false
-modify_image_extract_list:
-  - /tmp/builder.log
+libguestfs_mode: false
 
 # Without this wildcard, the deployment will fail with "no valid host found"
 # since nova will try to find defined flavors in the capabilities of the node