Packer keeps trying to pull a non existent source image

#### Overview of the Issue

I've noticed that one Packer CI job was running for a very long time: more than 30 minutes, when the average job's duration is less than 10 minutes. The following message was logged over and over again:

```
openstack.debian: Image not Active, retrying in 10 seconds
```

I killed the job and found the issue: the image declared in the `external_source_image_url` variable did not exist: the HTTP endpoint was returning a 404 error.

#### Reproduction Steps

Set the `external_source_image_url` variable to a non existent image.

### Plugin and Packer version

Packer 1.7.8
Openstack plugin 1.0.0

### Simplified Packer Buildfile

```
packer {
required_version = "1.7.8"
required_plugins {
openstack = {
version = "1.0.0"
source = "github.com/hashicorp/openstack"
}
}
}

source "openstack" "debian" {
cloud = "dc1"
external_source_image_format = "raw"
external_source_image_url = "http://cdimage.debian.org/cdimage/openstack/10.11.1-20211029/debian-10.11.1-20211029-openstack-amd64.raw"
image_min_disk = "10"
image_name = "bla"
flavor = "packer"
ssh_username = "debian"
}

build {
sources = ["source.openstack.debian"]
}
```
### Operating system and Environment details

Debian Buster

### Log Fragments and crash.log files

```
$ packer build debian.pkr.hcl
116openstack.debian: output will be in this color.
117==> openstack.debian: Loading flavor: packer
118 openstack.debian: Verified flavor. ID: 121d18c3-f0e0-4096-ba60-54c4050ea109
119==> openstack.debian: Creating temporary keypair: packer_61d470f3-fd3e-a797-819b-21b31030b544 ...
120==> openstack.debian: Created temporary keypair: packer_61d470f3-fd3e-a797-819b-21b31030b544
121==> openstack.debian: Creating image using external source image with name packer_61d470f3-fcb1-75b4-1c99-251728853883
122==> openstack.debian: Using disk format raw
123==> openstack.debian: Created image with ID 4964814c-7512-4293-879d-50b5b25b37cb
124==> openstack.debian: Importing External Source Image from URL http://cdimage.debian.org/cdimage/openstack/10.11.1-20211029/debian-10.11.1-20211029-openstack-amd64.raw
125 openstack.debian: Image not Active, retrying in 10 seconds
126 openstack.debian: Image not Active, retrying in 10 seconds
127 openstack.debian: Image not Active, retrying in 10 seconds
128 openstack.debian: Image not Active, retrying in 10 seconds
129 openstack.debian: Image not Active, retrying in 10 seconds
130 openstack.debian: Image not Active, retrying in 10 seconds
131 openstack.debian: Image not Active, retrying in 10 seconds
132 openstack.debian: Image not Active, retrying in 10 seconds
```

Không có tệp hoặc bài kiểm thử nào được nêu tên. Hãy bắt đầu bằng cách xác định phần xử lý external_source_image_url và vòng lặp retry trạng thái hình ảnh, sau đó tái hiện bằng một URL trả về 404. Phần hoàn tất cần bao gồm một lỗi có giới hạn hoặc kết thúc, kèm thông báo lỗi rõ ràng, thay vì retry lặp đi lặp lại.

Do mô hình lập chỉ mục viết ra từ nội dung của issue.