beaker-wizard: Accept more keys for attachments

Updated python-bugzilla uses different key names for attachment data.
This patch adds support for both "ispatch" and "is_patch", "filename"
and "file_name", "isobsolete" and "is_obsolete".

Bug: 929190
Change-Id: If4f969ccc20fb95474ca1e5a3a338e6709a31806