stx-tools: download scripts leave corrupted files behind

[Davlet Panech]

Brief Description
-----------------
Tarball & RPM download scripts in stx/tools sometimes leave corrupted files behind.

Details
-------
The problem is caused by the "wget" command, which doesn't handle download errors very well:

1) If the file can't be downloaded at all, *and* we use get with the -O flag, a zero-length output file is left behind. For example:

  # wget -O foo https://github.com/no/such/file
  --2021-11-05 16:30:09-- https://github.com/no/such/file
  Resolving github.com (github.com)... 140.82.113.3
  Connecting to github.com (github.com)|140.82.113.3|:443... connected.
  HTTP request sent, awaiting response... 404 Not Found
  2021-11-05 16:30:09 ERROR 404: Not Found.
  # echo $?
  8
  # ls -al foo
  -rw-r--r-- 1 dpanech users 0 Nov 5 16:30 foo

2) In some cases wget saves a partially downloaded file and yet returns 0 (success) to the shell. This happens if the download stalls mid-way, for example, *and* the web server doesn't support byte-ranges.

This is difficult to reproduce, but I observed it several times in the presence of a web proxy:

  # wget http://mirror.starlingx.cengn.ca:80/mirror/centos/github.com/kubernetes/kubernetes/archive/refs/tags/v1.19.13.tar.gz
  --2021-11-05 16:55:58-- http://mirror.starlingx.cengn.ca/mirror/centos/github.com/kubernetes /kubernetes/archive/refs/tags/v1.19.13.tar.gz
  Resolving mirror.starlingx.cengn.ca (mirror.starlingx.cengn.ca)... 135.84.106.45
  Connecting to mirror.starlingx.cengn.ca (mirror.starlingx.cengn.ca)|135.84.106.45|:80... connected.
  HTTP request sent, awaiting response... 200 OK
  Length: 33554674 (32M) [application/octet-stream]
  Saving to: ‘v1.19.13.tar.gz’

  55% [=====================================> ] 18,671,712 --.-K/s in 15m 17s

  2021-11-05 17:11:15 (19.9 KB/s) - Read error at byte 18671712/33554674 (Connection timed out). Retrying.

  --2021-11-05 17:11:16-- (try: 2) http://mirror.starlingx.cengn.ca/mirror/centos/github.com/kubernetes/kubernetes/archive/refs/tags/v1.19.13.tar.gz
  Connecting to mirror.starlingx.cengn.ca (mirror.starlingx.cengn.ca)|135.84.106.45|:80... connected.
  HTTP request sent, awaiting response... 416 Requested Range Not Satisfiable

      The file is already fully retrieved; nothing to do.

  # echo $?
  0

  # ls -al
  total 37792
  drwxr-xr-x 2 dpanech users 4096 Nov 5 16:55 .
  drwxrwxrwt. 754 root root 1339392 Nov 5 17:20 ..
  -rw-r--r-- 1 dpanech users 18671712 Nov 5 16:49 foo
  -rw-r--r-- 1 dpanech users 18671712 Nov 5 16:56 v1.19.13.tar.gz

Severity
--------
Major

Steps to Reproduce
------------------
N/A - See "Details" above

Expected Behavior
------------------
Failed downloads must not leave partial files behind

Actual Behavior
----------------
Failed downloads leave partial files behind.

Reproducibility
---------------
Intermittent

System Configuration
--------------------
N/A

Branch/Pull Time/Commit
-----------------------
master/2021-11-05

Last Pass
---------
N/A

Timestamp/Logs
--------------
N/A

Test Activity
-------------
N/A

Workaround
----------
N/A

[Davlet Panech (dpanech)]

This is fixed: https://review.opendev.org/c/starlingx/tools/+/817049

I misspelled the "Closes-Bug" annotation in the commit message, that's why Gerrit didn't link the patch.