arm image deploy: don't use HDD_1

Setting HDD_1 to %HDD_2% is broken in recent openQA:
https://github.com/os-autoinst/openQA/pull/3309#issuecomment-721906935
I count this as a bug, but we can solve it like this, I think -
we don't actually need to set this test up so carefully to only
have the disk image as HDD_1 and no HDD_2, we can actually just
let the disk image be HDD_2 and have an empty disk as HDD_1 and
the test still works, qemu will boot from the second disk and we
can upload it and everything's fine. So let's just go with that.

Signed-off-by: Adam Williamson <awilliam@redhat.com>

main.pm

@@ -343,7 +343,7 @@ sub load_postinstall_tests() {
     }
 
     # we should shut down before uploading disk images
-    if (get_var("STORE_HDD_1") || get_var("PUBLISH_HDD_1")) {
+    if (get_var("STORE_HDD_1") || get_var("STORE_HDD_2") || get_var("PUBLISH_HDD_1")) {
         autotest::loadtest "tests/_console_shutdown.pm";
     }
     

templates.fif.json

@@ -874,11 +874,10 @@
                 "fedora-Workstation-raw_xz-raw.xz-aarch64-*-aarch64": 12
             },
             "settings": {
-                "HDD_1": "%HDD_2%",
                 "IMAGE_DEPLOY": "1",
                 "INSTALL_NO_USER": "1",
-                "NUMDISKS": "1",
-                "STORE_HDD_1": "disk_%FLAVOR%_%MACHINE%.qcow2"
+                "NUMDISKS": "2",
+                "STORE_HDD_2": "disk_%FLAVOR%_%MACHINE%.qcow2"
             }
         },
         "install_asian_language": {