conf: Add helper do clear disk source authentication struct

Add virDomainDiskAuthClear to help cleaning out the struct in other
places too.

src/conf/domain_conf.c

@@ -1201,12 +1201,9 @@ void virDomainDiskDefFree(virDomainDiskDefPtr def)
     VIR_FREE(def->driverName);
     virStorageFileFreeMetadata(def->backingChain);
     VIR_FREE(def->mirror);
-    VIR_FREE(def->auth.username);
     VIR_FREE(def->wwn);
     VIR_FREE(def->vendor);
     VIR_FREE(def->product);
-    if (def->auth.secretType == VIR_DOMAIN_DISK_SECRET_TYPE_USAGE)
-        VIR_FREE(def->auth.secret.usage);
     virStorageEncryptionFree(def->encryption);
     virDomainDeviceInfoClear(&def->info);
 
@@ -1217,10 +1214,24 @@ void virDomainDiskDefFree(virDomainDiskDefPtr def)
     }
 
     virDomainDiskHostDefFree(def->nhosts, def->hosts);
+    virDomainDiskAuthClear(def);
 
     VIR_FREE(def);
 }
 
+
+void
+virDomainDiskAuthClear(virDomainDiskDefPtr def)
+{
+    VIR_FREE(def->auth.username);
+
+    if (def->auth.secretType == VIR_DOMAIN_DISK_SECRET_TYPE_USAGE)
+        VIR_FREE(def->auth.secret.usage);
+
+    def->auth.secretType = VIR_DOMAIN_DISK_SECRET_TYPE_NONE;
+}
+
+
 void virDomainDiskHostDefClear(virDomainDiskHostDefPtr def)
 {
     if (!def)

src/conf/domain_conf.h

@@ -2209,6 +2209,7 @@ void virDomainGraphicsDefFree(virDomainGraphicsDefPtr def);
 void virDomainInputDefFree(virDomainInputDefPtr def);
 void virDomainDiskDefFree(virDomainDiskDefPtr def);
 void virDomainLeaseDefFree(virDomainLeaseDefPtr def);
+void virDomainDiskAuthClear(virDomainDiskDefPtr def);
 void virDomainDiskHostDefClear(virDomainDiskHostDefPtr def);
 void virDomainDiskHostDefFree(size_t nhosts, virDomainDiskHostDefPtr hosts);
 virDomainDiskHostDefPtr virDomainDiskHostDefCopy(size_t nhosts,

src/libvirt_private.syms

@@ -180,6 +180,7 @@ virDomainDeviceFindControllerModel;
 virDomainDeviceInfoCopy;
 virDomainDeviceInfoIterate;
 virDomainDeviceTypeToString;
+virDomainDiskAuthClear;
 virDomainDiskBusTypeToString;
 virDomainDiskCacheTypeFromString;
 virDomainDiskCacheTypeToString;