Define common mirrors not in OE-Core anymore

This is resting place for recipe angstrom uses
but the common URLs as were defined in bitbake.conf
are now gone after commit

commit 3b333896c71689c664475d53daed52404bf6b21b
Author: Phil Blundell <pb@pbcl.net>
Date:   Thu Nov 14 18:15:46 2013 +0000

    bitbake.conf: Remove obsolete/unused MIRROR cruft

Signed-off-by: Khem Raj <raj.khem@gmail.com>