gen-upgrade-proposal.sh variable name spelling is inconsistent with forum posts

[gibson042]

What is the Problem Being Solved?

Compare scripts/gen-upgrade-proposal.sh to e.g. [Proposal #71] agoric-upgrade-14

 COMMIT_ID=$(git rev-parse HEAD)
-ZIPURL=https://github.com/Agoric/agoric-sdk/archive/$COMMIT_ID.zip
 
-echo "Verifying archive is at $ZIPURL..." 1>&2
-zipfile=$(mktemp)
-trap 'rm -f "$zipfile"' EXIT
-curl -L "$ZIPURL" -o "$zipfile"
+ZIP_URL="https://github.com/Agoric/agoric-sdk/archive/${COMMIT_ID}.zip"
 
-echo "Generating SHA-256 checksum..." 1>&2
-checksum=sha256:$(shasum -a 256 "$zipfile" | cut -d' ' -f1)
+CHECKSUM=sha256:$(curl -L "$ZIP_URL" -o- | shasum -a 256 | cut -d' ' -f1)
 
-info="{\"binaries\":{\"any\":\"$ZIPURL//agoric-sdk-$COMMIT_ID?checksum=$checksum\"},\"source\":\"$ZIPURL?checksum=$checksum\"}"
+UPGRADE_INFO="{\"binaries\":{\"any\":\"$ZIP_URL//agoric-sdk-${COMMIT_ID}?checksum=$CHECKSUM\"},\"source\":\"$ZIP_URL?checksum=$CHECKSUM\"}"
+top-node-on-err = {{ .Streaming.ABCI.StopNodeOnErr }}

Description of the Design

Since we're demonstrably comfortable with sharing the forum post representation, adopt its patterns into gen-upgrade-proposal.sh.

Security Considerations

None.

Scaling Considerations

n/a

Test Plan

This code is well-exercised.

Upgrade Considerations

Functionality must not change.