How to test:
- Ensure that libplayit2.sh can not be found in any of these directories:
- current directory
- Call the main script by giving it as its first argument something that is not a file
- Call the main script by giving it as its first argument a file that is not a supported installer
With 2.10.3, using some shells including bash, the script will fail after outputing something similar to:
return: can only `return' from a function or sourced script
With this patch, no matter the shell, the script will exit with an explicit error message but without a shell error.