In comparison function for 'list_sort()' we use key type to distinguish between
node types. However, we have a bit simper way to detect node type -
'snod->type'. This more logical to use, comparing to decoding key types. Also
allows to get rid of 2 local variables.
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>