enlarge the timeout of test_delete_exported_image.py
enlarge the timeout of test_delete_exported_image.py

zstackio/zstack-woodpecker,zstackorg/zstack-woodpecker,zstackorg/zstack-woodpecker,zstackio/zstack-woodpecker,zstackorg/zstack-woodpecker,zstackio/zstack-woodpecker