fixing podman build issue (#32131)

Signed-off-by: Smit Kadvani <smit.kadvani@gmail.com>
Co-authored-by: Smit Shaileshbhai Kadvani <kadvani@meta.com>
Co-authored-by: Lu Fang <30275821+houseroad@users.noreply.github.com>

docker/Dockerfile.rocm

@@ -39,6 +39,8 @@ ONBUILD COPY ./ vllm/
 FROM base AS fetch_vllm_1
 ARG VLLM_REPO="https://github.com/vllm-project/vllm.git"
 ARG VLLM_BRANCH="main"
+ENV VLLM_REPO=${VLLM_REPO}
+ENV VLLM_BRANCH=${VLLM_BRANCH}
 ONBUILD RUN git clone ${VLLM_REPO} \
 	    && cd vllm \
 	    && git fetch -v --prune -- origin ${VLLM_BRANCH} \