LP#1527731: Stablize eg_cache_hash key used for autogen (and other) cache busting

LP#1527731: Stablize eg_cache_hash key used for autogen (and other) cache busting

Because of the way Perl after 5.18 randomizes internal hash keys and key
retrieval order, each run of autogen.sh produces a different key.  What we want
is the same key for the same data on the same day, regardless of anything else.
So, here we tell Perl to use a repeatable hash key order.

Signed-off-by: Mike Rylander <mrylander@gmail.com>