LXC: trivially support flag VIR_DRV_FEATURE_TYPED_PARAM_STRING

Fix lxcDomainGetMemoryParameters and lxcDomainGetSchedulerParametersFlags:
virsh -c lxc:/// memtune DOMAIN
error: Unable to get number of memory parameters
error: unsupported flags (0x4) in function lxcDomainGetMemoryParameters

Introduced by commit 399394.
Signed-off-by: NChen Hanxiao <chenhanxiao@cn.fujitsu.com>
Signed-off-by: NJán Tomko <jtomko@redhat.com>

src/lxc/lxc_driver.c

@@ -895,7 +895,11 @@ lxcDomainGetMemoryParameters(virDomainPtr dom,
     size_t i;
 
     virCheckFlags(VIR_DOMAIN_AFFECT_LIVE |
-                  VIR_DOMAIN_AFFECT_CONFIG, -1);
+                  VIR_DOMAIN_AFFECT_CONFIG |
+                  VIR_TYPED_PARAM_STRING_OKAY, -1);
+
+    /* We don't return strings, and thus trivially support this flag.  */
+    flags &= ~VIR_TYPED_PARAM_STRING_OKAY;
 
     if (!(vm = lxcDomObjFromDomain(dom)))
         goto cleanup;
@@ -1993,7 +1997,11 @@ lxcDomainGetSchedulerParametersFlags(virDomainPtr dom,
     virLXCDomainObjPrivatePtr priv;
 
     virCheckFlags(VIR_DOMAIN_AFFECT_LIVE |
-                  VIR_DOMAIN_AFFECT_CONFIG, -1);
+                  VIR_DOMAIN_AFFECT_CONFIG |
+                  VIR_TYPED_PARAM_STRING_OKAY, -1);
+
+    /* We don't return strings, and thus trivially support this flag.  */
+    flags &= ~VIR_TYPED_PARAM_STRING_OKAY;
 
     if (!(vm = lxcDomObjFromDomain(dom)))
         goto cleanup;