Bump HDD size for LVM resize tests

With the 2G ESP change, we need bigger disks for these tests to
work correctly. On BIOS the test still just about works because
anaconda rounds the remaining space after BIOS boot partition
and /boot to 14G, but it seems fragile to rely on this. On UEFI
(aarch64), anaconda sees a max of 12G remaining after 2G ESP
and 1G /boot, so the test fails because we cannot size to 13G.
Give the test an extra 2G, this should be sufficient to make
sure it's valid on all platforms.

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

templates.fif.json

@@ -860,6 +860,7 @@
             "settings": {
                 "PARTITIONING": "custom_blivet_resize_lvm",
                 "HDD_1": "disk_%FLAVOR%_%MACHINE%.qcow2",
+                "HDDSIZEGB": "17",
                 "INSTALL": "1",
                 "POSTINSTALL": "disk_custom_resize_lvm_postinstall",
                 "ROOT_PASSWORD": "weakpassword",
@@ -875,6 +876,7 @@
             "settings": {
                 "PARTITIONING": "custom_resize_lvm",
                 "HDD_1": "disk_%FLAVOR%_%MACHINE%.qcow2",
+                "HDDSIZEGB": "17",
                 "INSTALL": "1",
                 "ROOT_PASSWORD": "weakpassword",
                 "START_AFTER_TEST": "install_lvm_ext4"