Increase the ext4 default commit age

Both the VM and EXT4 have a "commit to disk after X seconds" time.
Currently the EXT4 time is shorter than our VM time, which is a bit
suboptional,
it's better for performance to let the VM do the writeouts in bulk
rather than something deep in the journalling layer.

(DISTRO TWEAK -- NOT FOR UPSTREAM)

Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: Jose Carlos Venegas Munoz <jose.carlos.venegas.munoz@intel.com>
Signed-off-by: Diab Neiroukh <lazerl0rd@thezest.dev>