schema: Allow space character in disk vendor/product

The hex range already tried to allow for it, but it wasn't using
the correct XML hex syntax. Fix it, and test it

docs/schemas/domaincommon.rng

@@ -1165,14 +1165,16 @@
       <optional>
         <element name="vendor">
           <data type="string">
-            <param name="pattern">[x20-x7E]{0,8}</param>
+            <!-- All printable characters -->
+            <param name="pattern">[&#x20;-&#x7E;]{0,8}</param>
           </data>
         </element>
       </optional>
       <optional>
         <element name="product">
           <data type="string">
-            <param name="pattern">[x20-x7E]{0,16}</param>
+            <!-- All printable characters -->
+            <param name="pattern">[&#x20;-&#x7E;]{0,16}</param>
           </data>
         </element>
       </optional>

tests/qemuxml2argvdata/qemuxml2argv-disk-scsi-disk-vpd.args

@@ -24,6 +24,6 @@ QEMU_AUDIO_DRV=none \
 -device scsi-cd,bus=scsi0.0,channel=0,scsi-id=0,lun=0,drive=drive-scsi0-0-0-0,\
 id=scsi0-0-0-0,vendor=SEAGATE,product=ST3146707LC \
 -drive file=/dev/HostVG/QEMUGuest2,format=raw,if=none,id=drive-scsi1-0-0 \
--device scsi-hd,bus=scsi1.0,scsi-id=0,drive=drive-scsi1-0-0,id=scsi1-0-0,\
-vendor=SEAGATE,product=ST3567807GD \
+-device 'scsi-hd,bus=scsi1.0,scsi-id=0,drive=drive-scsi1-0-0,id=scsi1-0-0,\
+vendor=SEA GATE,product=ST67 807GD' \
 -device virtio-balloon-pci,id=balloon0,bus=pci.0,addr=0x5

tests/qemuxml2argvdata/qemuxml2argv-disk-scsi-disk-vpd.xml

@@ -26,8 +26,8 @@
       <source dev='/dev/HostVG/QEMUGuest2'/>
       <target dev='sdb' bus='scsi'/>
       <readonly/>
-      <vendor>SEAGATE</vendor>
-      <product>ST3567807GD</product>
+      <vendor>SEA GATE</vendor>
+      <product>ST67 807GD</product>
       <address type='drive' controller='1' bus='0' target='0' unit='0'/>
     </disk>
     <controller type='usb' index='0'/>

tests/qemuxml2xmloutdata/qemuxml2xmlout-disk-scsi-disk-vpd.xml

@@ -26,8 +26,8 @@
       <source dev='/dev/HostVG/QEMUGuest2'/>
       <target dev='sdb' bus='scsi'/>
       <readonly/>
-      <vendor>SEAGATE</vendor>
-      <product>ST3567807GD</product>
+      <vendor>SEA GATE</vendor>
+      <product>ST67 807GD</product>
       <address type='drive' controller='1' bus='0' target='0' unit='0'/>
     </disk>
     <controller type='usb' index='0'>