generation: Update upload script to match new networkcache version 0.26

To avoid json-in-json-in-json the metadata is directly put in a file and
the values do not need to be quoted anymore.
The current configuration features only json-in-json.

generation/40upload-image.sh

@@ -20,15 +20,14 @@ version_to_list () {
 }
 kernel_revision_arch=$(uname -r)
 
-# the keys "file" and "urlmd5" are sometimes mandatory in shadir metadata
-# and are defined here only for the sake of shadir compliance
+# strings have to be quoted so that the file is decoded as valid json
 json_metadata="{ \
 	\"server-group\": \"$SERVER_GROUP\", \
-	\"kernel-version\": \"$(version_to_list $(uname -v | cut -d' ' -f4))\", \
+	\"kernel-version\": $(version_to_list $(uname -v | cut -d' ' -f4)), \
 	\"kernel-revision\": \"${kernel_revision_arch%-*}\", \
-	\"mca-version\": \"$(version_to_list $MCA_VERSION)\", \
-	\"flb-version\": \"$(version_to_list $FLB_VERSION)\", \
-	\"plg-version\": \"$(version_to_list $PLG_VERSION)\", \
+	\"mca-version\": $(version_to_list $MCA_VERSION), \
+	\"flb-version\": $(version_to_list $FLB_VERSION), \
+	\"plg-version\": $(version_to_list $PLG_VERSION), \
 	\"timestamp\": $(date +%s), \
 	\"comment\": \"$hash_comment\" \
 }"