Add -e MASTER_PLIST_URL to change the input config.plist at runtime.

Dockerfile.naked

@@ -122,6 +122,7 @@ CMD sudo chown -R $(id -u):$(id -g) /dev/kvm /dev/snd "${IMAGE_PATH}" "${BOOTDIS
     ; } \
     ; [[ "${GENERATE_UNIQUE}" == true ]] && { \
         ./Docker-OSX/custom/generate-unique-machine-values.sh \
+            --master-plist-url="${MASTER_PLIST_URL}" \
             --count 1 \
             --tsv ./serial.tsv \
             --bootdisks \
@@ -133,6 +134,7 @@ CMD sudo chown -R $(id -u):$(id -g) /dev/kvm /dev/snd "${IMAGE_PATH}" "${BOOTDIS
     ; [[ "${GENERATE_SPECIFIC}" == true ]] && { \
             source "${ENV:=/env}" \
             || ./Docker-OSX/custom/generate-specific-bootdisk.sh \
+            --master-plist-url="${MASTER_PLIST_URL}" \
             --model "${DEVICE_MODEL}" \
             --serial "${SERIAL}" \
             --board-serial "${BOARD_SERIAL}" \