Fix virDomainDeviceInfoIsSet() to check all struct fields

The virDomainDeviceInfoIsSet API was only checking if an
address or alias was set in the struct. Thus if only a
rom bar setting / filename, boot index, or USB master
value was set, they could be accidentally dropped when
formatting XML
(cherry picked from commit 2c195fdb)

Conflicts:

	src/conf/domain_conf.c

(crobinso: some elements aren't in maint branch, drop them)

src/conf/domain_conf.c

@@ -1508,14 +1508,16 @@ int virDomainDeviceVirtioSerialAddressIsValid(
 }
 
 
-static int
+static bool
 virDomainDeviceInfoIsSet(virDomainDeviceInfoPtr info, unsigned int flags)
 {
     if (info->type != VIR_DOMAIN_DEVICE_ADDRESS_TYPE_NONE)
-        return 1;
+        return true;
     if (info->alias && !(flags & VIR_DOMAIN_XML_INACTIVE))
-        return 1;
-    return 0;
+        return true;
+    if (info->mastertype != VIR_DOMAIN_CONTROLLER_MASTER_NONE)
+        return true;
+    return false;
 }
 
 

src/conf/domain_conf.h

@@ -138,6 +138,10 @@ struct _virDomainDeviceUSBMaster {
 typedef struct _virDomainDeviceInfo virDomainDeviceInfo;
 typedef virDomainDeviceInfo *virDomainDeviceInfoPtr;
 struct _virDomainDeviceInfo {
+    /* If adding to this struct, ensure that
+     * virDomainDeviceInfoIsSet() is updated
+     * to consider the new fields
+     */
     char *alias;
     int type;
     union {