tests/avocado: boot ppc64 pseries to Linux VFS mount

This machine can boot Linux to VFS mount, so don't stop in early boot.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Reviewed-by: Cédric Le Goater <clg@kaod.org>
Signed-off-by: Cédric Le Goater <clg@kaod.org>

tests/avocado/ppc_pseries.py

@@ -31,5 +31,5 @@ def test_ppc64_pseries(self):
         self.vm.add_args('-kernel', kernel_path,
                          '-append', kernel_command_line)
         self.vm.launch()
-        console_pattern = 'Kernel command line: %s' % kernel_command_line
+        console_pattern = 'VFS: Cannot open root device'
         wait_for_console_pattern(self, console_pattern, self.panic_message)