Update rs_id.json

I added db_codes of db_xref in insdc, which are available in Identifiers.org.
# mapping data the following URL:
# https://docs.google.com/a/g.nig.ac.jp/spreadsheets/d/1j_wZgsjah4ETiNpRcxjr6g7zfU4mWVZuc6A2Ot6DCU0/edit#gid=0
Bug fixed in json format.
Merge pull request #3 from tfuji/patch-1

Update rs_id.json for converting the db_codes of /db_xref qualifier in insdc