vsh: Using VSH_REQUIRE_OPTION rather than virReportError

Correcting the error reporting method by using VSH_REQUIRE_OPTION
instead of virReportError
Signed-off-by: NKothapally Madhu Pavan <kmp@linux.vnet.ibm.com>

tools/virsh-domain.c

@@ -10419,6 +10419,7 @@ cmdMigrate(vshControl *ctl, const vshCmd *cmd)
 
     VSH_EXCLUSIVE_OPTIONS("live", "offline");
     VSH_EXCLUSIVE_OPTIONS("timeout-suspend", "timeout-postcopy");
+    VSH_REQUIRE_OPTION("postcopy-after-precopy", "postcopy");
 
     if (!(dom = virshCommandOptDomain(ctl, cmd, NULL)))
         return false;
@@ -10450,12 +10451,6 @@ cmdMigrate(vshControl *ctl, const vshCmd *cmd)
     }
 
     if (vshCommandOptBool(cmd, "postcopy-after-precopy")) {
-        if (!vshCommandOptBool(cmd, "postcopy")) {
-            virReportError(VIR_ERR_ARGUMENT_UNSUPPORTED, "%s",
-                          _("--postcopy-after-precopy can only be used with "
-                            "--postcopy"));
-            goto cleanup;
-        }
         iterEvent = virConnectDomainEventRegisterAny(
                             priv->conn, dom,
                             VIR_DOMAIN_EVENT_ID_MIGRATION_ITERATION,