localedata: Add en_SE for ISO8601 dates

localedata: Add en_SE for ISO8601 dates

On a Linux system you have two sources for locales: glibc and ICU.

ICU offeres a lot more languages than glibc. Especially when it comes to
en_*.

If you have an English system and want to use ISO8601 for date and time
format there is only one locale which can be used for that: en_SE

However ICU offers en_SE and glibc doesn't. If you set LC_TIME=en_SE a
lot of application wont start, because the locale is not known to glibc.

https://sourceware.org/bugzilla/show_bug.cgi?id=33190

Signed-off-by: Andreas Schneider <asn@cryptomilk.org>
Reviewed-by: Mike FABIAN <mfabian@redhat.com>