XML export created with invalid encoding declaration

If JIRA's encoding is set to something like 'ISO8859_1', then the XML export apparently fails, because the encoding declaration is invalid:

/tmp/export.xml:1: error: Unsupported encoding ISO8859_1
<?xml version="1.0" encoding="ISO8859_1"?>

The workaround is simply to use 'iso-8859-1' as the encoding, which is valid for XML and Java.