rename LLAMASTACK_PORT to LLAMA_STACK_PORT for consistency with other env vars (#744)

# What does this PR do?

Rename environment var for consistency

## Test Plan

No regressions

## Sources

## Before submitting

- [X] This PR fixes a typo or improves the docs (you can dismiss the
other checks if that's the case).
- [X] Ran pre-commit to handle lint / formatting issues.
- [X] Read the [contributor
guideline](https://github.com/meta-llama/llama-stack/blob/main/CONTRIBUTING.md),
Pull Request section?
- [X] Updated relevant documentation.
- [ ] Wrote necessary unit or integration tests.

---------

Signed-off-by: Yuan Tang <terrytangyuan@gmail.com>
Co-authored-by: Yuan Tang <terrytangyuan@gmail.com>

distributions/remote-vllm/compose.yaml

@@ -85,7 +85,7 @@ services:
       - SQLITE_STORE_DIR=${SQLITE_STORE_DIR:-$HOME/.llama/distributions/remote-vllm}
       - SAFETY_MODEL=${SAFETY_MODEL:-meta-llama/Llama-Guard-3-1B}
     ports:
-      - "${LLAMASTACK_PORT:-5001}:${LLAMASTACK_PORT:-5001}"
+      - "${LLAMA_STACK_PORT:-5001}:${LLAMA_STACK_PORT:-5001}"
     # Hack: wait for vLLM server to start before starting docker
     entrypoint: bash -c "sleep 60; python -m llama_stack.distribution.server.server --yaml_config /root/llamastack-run-remote-vllm.yaml --port 5001"
     deploy: