plugins: Fix shellcheck warnings on already linted files

[NoahGorny]

For some reason, running lint_clean_files.sh locally resulted in some errors for me, although it is ran on every PR...

Description

Fix small shellcheck quoting warnings

Motivation and Context

Clears up lint_clean_files.sh to not error out

How Has This Been Tested?

lint ran, tests as well

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

Checklist:

• My code follows the code style of this project.
• I have read the CONTRIBUTING document.
• If I have added a new file, I also added it to clean_files.txt and formatted it using lint_clean_files.sh.
• I have added tests to cover my changes, and all the new and existing tests pass.

[gaelicWizard]

I think the brackets should be inside the quotes

[NoahGorny]

It does not really matter, but it does look nicer when the brackets are inside, changed

[gaelicWizard]

Behavior is subtly different in some ways, consider:

cd /tmp
touch "a"
touch "b"
echo ["ab"]

The intent is clearly the characters ab printed, but the result is a b because the [/] is making it a pattern to be globbed and it's matching on the files in the directory.

Then, try this:

cd /tmp
touch "a"
rm -f "b"
echo ["ab"]

Again, the intent would be to see ab, but the result is just a because the globbing matching the pattern but only partially.

My rule of thumb is: if you want that thing, then quote it.

[NoahGorny]

I see, you are very correct!