Have salt-cloud clean up tmp files

[clarkperkins]

What does this PR do?

We ran in to an issue with our root partition filling up due to thousands of tmp files being left behind by salt-cloud.

What issues does this PR fix or reference?

none

Previous Behavior

~5 tmp* files were left in the /tmp directory for every host launched with salt-cloud

New Behavior

tmp files in /tmp are cleaned up by salt-cloud

Tests written?

No

Please review Salt's Contributing Guide for best practices.

[terminalmage]

This still won't fix instances where an exception is raised before we get to the os.remove(). It would probably be best to put this in a try/finally.

[clarkperkins]

Ah, good point - I will add that

[terminalmage]

You hit upon some good points in raising this issue, but I took a look and came up with my own solution which I think might work better:

https://github.com/saltstack/salt/pull/36484/files

For one, you made me realize that whoever created this issue wrote the tempfile code in the first place was leaving open file descriptors, which my PR fixes by calling os.close() on them. Also, since we only deal with the temp file in a very small block of code, the try/finally block doesn't need to be so big. Finally, if neither contents nor local_file were passed, we'd get a NameError when we build the SSH command below. Your PR would have fixed this last thing but my PR also adds warning logging which might help in troubleshooting.

What do you think?

[terminalmage]

Actually, mkstemp returns an os-level filehandle, so opening the path for writing is entirely unnecessary, we should be using os.write() here. I'm updating my PR.

[terminalmage]

Closing in favor of #36484.