anvil-generate-iso script fails without fullpath

[mh-alteeve]

Using anvil-generate-iso with two paths as shown below produces an error, "[ Error ] - Source: [./Downloads/CentOS-6.10-x86_64-bin-DVD1.iso,./Downloads/CentOS-6.10-x86_64-bin-DVD2.iso] doesn't exist!"

Steps to Reproduce:

1. Fetch anvil-generate-iso script
2. make executable
3. Fetch anvil-generate-iso dependencies and the latest pair of DVD isos for CentOS v6
4. Run the anvil-generate-iso script with the options "--source ./rel/path/to/Centos6.x-DVD1.iso,./rel/path/to/Centos6.x-DVD2.iso

Expected Result:
Script finds the isos and begins creating the install media

Observed Result:
Script fails with "[ Error ] - Source: [./Downloads/CentOS-6.10-x86_64-bin-DVD1.iso,./Downloads/CentOS-6.10-x86_64-bin-DVD2.iso] doesn't exist!"

Specifying the full path "/home/$whoami/Downloads/Centos-6.10..." seems to be a valid workaround.