test-appliance: temporary workaround to fix GCE networking breakage

For now, diable running updating to the latest version of Debian
packages to work around the virtio-net device not getting detected
with custom kernels built with the install-kconfig kernel
configuration.  (Veriied with a 5.15.79 and 6.10-rc5 kernel, although
the 6.1 Debin kernel works; so it must be some kind of kernel config
or some kind of initrd construction issue.)

The packages that are updated with the "apt-get upgrade" are:

exim4-config 4.96-15+deb12u4 --> 4.96-15+deb12u5
exim4-base 4.96-15+deb12u4 --> 4.96-15+deb12u5 over
exim4-daemon-light 4.96-15+deb12u4 --> 4.96-15+deb12u5
google-guest-agent 1:20240528.00-g1 --> 1:20240701.00-g1
google-compute-engine-oslogin 1:20240415.00-g1+deb12 --> 1:20240701.00-g1+deb12

Where the last two are the most likely culprits.

Signed-off-by: Theodore Ts'o <[email protected]>

test-appliance/gce-xfstests-bld.sh

@@ -214,7 +214,8 @@ if test -n "$NEW_SUITE" -a "$OLD_SUITE" != "$NEW_SUITE" ; then
     logger -s "Update to $NEW_SUITE complete"
 else
     apt-get update
-    apt-get -y --with-new-pkgs upgrade
+    # Temporary workaround to fix networking breakage
+    # apt-get -y --with-new-pkgs upgrade
 fi
 
 if test "$NEW_SUITE" = "buster" ; then