Bad JSON response for queries with ?on_error=stop and when errors exist

Under certain circumstances, when using ?on_error=stop and errors happened during query execution, the server now returns invalid JSON response. Examples:

],"errors":[

{"from":"http://192.168.1.80:9501/_view_merge/?reduce=false&stale=false&on_error=stop&limit=10","reason":"timeout"}

]
}

{"total_rows":0,"rows":[]
{"total_rows":0,"rows":[]
,
"errors":[

{"from":"http://192.168.1.80:9501/_view_merge/?reduce=false&stale=false&on_error=stop&limit=10","reason":"timeout"}

]
}

This is due to a missing change in commit b4391e4e27319c504b74260df102a19ac090c81e (MB-6988).