COUCHDB-627 - Support all timezones
COUCHDB-627 - Support all timezones

Some timezones are incorrectly handled by OTP's calendar module. The
ironic thing is that we only ever need the time in GMT (for HTTP
response headers and the log file).

This patch duplicates httpd_util:rfc1123_date/0 and /1 but uses
universal time everywhere, avoiding the broken conversion code.

Also relates to COUCHDB-1513, a duplicate of COUCHDB-627.

fkaempfer/couchdb,fkaempfer/couchdb,fkaempfer/couchdb,fkaempfer/couchdb,fkaempfer/couchdb,fkaempfer/couchdb