Instead of sorting and reversing, sort by inverse order
Instead of sorting and reversing, sort by inverse order

This keeps the code slightly more readable. Also, while there,
also remove the hack of avoiding the dangerous "head" function
by using the (equally incomplete, but not checked for) "last"
function.

Signed-off-by: Klaus Aehlig <4ce51de36d9068cd7db2eec1151e0f3f95419008@google.com>
Reviewed-by: Petr Pudlak <9d19625f8ee825a2c398462ed335cbcf98f79c32@google.com>

bitemyapp/ganeti,mbakke/ganeti,bitemyapp/ganeti,onponomarev/ganeti,onponomarev/ganeti,ganeti/ganeti,leshchevds/ganeti,mbakke/ganeti,leshchevds/ganeti,ganeti/ganeti,mbakke/ganeti,leshchevds/ganeti,andir/ganeti,ganeti/ganeti,andir/ganeti,andir/ganeti