Fix early variable resolution for Equinox build websites

Author: HannesWell

sites/equinox/build/index.html

@@ -68,7 +68,9 @@ <h3 id="other">Other Information</h3>
 	<script>
 		loadPageData('buildproperties.json', data => {
 			data.buildTypeName = getBuildTypeName(data)
-			data.releaseShortUnderscore = data.releaseShort.replace('.', '_')
+			if (data.releaseShort) {
+				data.releaseShortUnderscore = data.releaseShort.replace('.', '_')
+			}
 			return data
 		})