qemu: Reset post-copy capability after migration

Unlike other migration capabilities, post-copy is also set on the
destination host which means it doesn't disappear once domain is
migrated. As a result of that other functionality which internally uses
migration to a file (virDomainManagedSave, virDomainSave,
virDomainCoreDump) may fail after migration because the post-copy
capability is still set.

https://bugzilla.redhat.com/show_bug.cgi?id=1374718

Signed-off-by: Jiri Denemark <jdenemar@redhat.com>

src/qemu/qemu_migration.c

@@ -6418,6 +6418,9 @@ qemuMigrationFinish(virQEMUDriverPtr driver,
          */
         if (inPostCopy)
             VIR_FREE(priv->job.completed);
+
+        qemuMigrationSetPostCopy(driver, vm, false,
+                                 QEMU_ASYNC_JOB_MIGRATION_IN);
     }
 
     qemuMigrationJobFinish(driver, vm);