doc: replace x-root with rootdir for usb-mtp

Signed-off-by: Bandan <bsd@redhat.com>
Message-id: 20180907220851.9658-3-bsd@redhat.com
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>

qemu-doc.texi

@@ -943,7 +943,7 @@ for details
 Bulk-only transport storage device, see
 @url{https://git.qemu.org/?p=qemu.git;a=blob_plain;f=docs/usb-storage.txt,usb-storage.txt}
 for details here, too
-@item usb-mtp,x-root=@var{dir}
+@item usb-mtp,rootdir=@var{dir}
 Media transfer protocol device, using @var{dir} as root of the file tree
 that is presented to the guest.
 @item usb-host,hostbus=@var{bus},hostaddr=@var{addr}

scripts/device-crash-test

@@ -125,7 +125,7 @@ ERROR_WHITELIST = [
     {'device':'tpm-tis', 'expected':True},                 # tpm_tis: backend driver with id (null) could not be found
     {'device':'unimplemented-device', 'expected':True},    # property 'size' not specified or zero
     {'device':'usb-braille', 'expected':True},             # Property chardev is required
-    {'device':'usb-mtp', 'expected':True},                 # x-root property must be configured
+    {'device':'usb-mtp', 'expected':True},                 # rootdir property must be configured
     {'device':'usb-redir', 'expected':True},               # Parameter 'chardev' is missing
     {'device':'usb-serial', 'expected':True},              # Property chardev is required
     {'device':'usb-storage', 'expected':True},             # drive property not set