(TCotten) Clean up temporary cookie jar files created by makeCurl()

* Previous version of the script left temporary files behind
* Avoids issues with the /tmp folder filling up with 65535 files and crashing other services such as MySQL

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The makeCurl() function fails to clean up the temporary cookie jar files it creates in some environments.

This can cause errors in the /tmp folder where 65535 files block other services from using the folder, such as MySQL, leading to an Error 28.

I've made a pull request with a proposed fix.