Fix variable names for $remainingPackages

[danieljurek]

This PR fixes the issue where new preview packages are not being properly onboarded in the docs.

• Resulting changes from running fixed onboarding script -- https://github.com/Azure/azure-docs-sdk-java/pull/2106/files
• Docs CI running with this change -- https://apidrop.visualstudio.com/Content%20CI/_build/results?buildId=250792&view=results
• docindex pipeline execution -- https://dev.azure.com/azure-sdk/internal/_build/results?buildId=1077681&view=results

@scbedd @mssfang

[scbedd]

🚀🚀 🚀 🚀 🚀

[scbedd]

@danieljurek apparently these changes makes it so that we can't NOT error out if there is an issue during the find dependencies stage of the script.

It's completing all the way to the end, then melting.

[danieljurek]

This is ready for review now @weshaggard

While these changes should go in the complete fix will depend on merging: Azure/azure-sdk-tools#1977

Until then the docindex pipelines can fail if the last invocation of an external command (e.g. mvn in the case of Java) exits with a nonzero exit code.