Fix import job to provide valid disk-formats list to tempest

Recent changes does not allow image conversion to convert an image
having AMI disk format for image. Passing list of disk-formats to
each import job which will now use qcow2 as default disk-format to
create the image.

Conflicts: .zuul.yaml

Change-Id: I712b304ebe168705ec2793626f5d64135ad6d458
(cherry picked from commit 244ccb6)
(cherry picked from commit f98e9ae)
(cherry picked from commit 02732c2)

Author: elajkat

.zuul.yaml

@@ -238,6 +238,11 @@
                 "glance_devstack_test":"doyouseeme?"
             image_conversion:
               output_format: raw
+        test-config:
+          "$TEMPEST_CONFIG":
+            image:
+              image_caching_enabled: True
+              disk_formats: qcow2,ari,aki,vhd,vmdk,raw,ami,vdi,iso,vhdx
 
 - job:
     name: glance-multistore-cinder-import