Rename sdk-persistent-disk to sdk-persistent-disk-sysroot

This makes the test case name more explicit and keeps consistency with
the rest of the psdk tests.

Signed-off-by: Luis Araujo <luis.araujo@collabora.co.uk>
4 jobs for apertis/v2021dev1 in 1 minute and 10 seconds (queued for 2 seconds)
Status Job ID Name Coverage
  Test
passed #283058
test

00:00:36

passed #283057
test-renderer

00:00:23

 
  Deploy
passed #283059
pages

00:00:33

passed pages:deploy

00:00:01