Cumulus: only set sampling-rate on a port if the desired rate changes. This avoids peturbations in the sFlow feed that manifest when sampling-rate is set repeatedly.

git-svn-id: svn://svn.code.sf.net/p/host-sflow/code@481 c0bd136a-9412-4574-afac-2923e5188ea6
Set version number to 1.26.1

git-svn-id: svn://svn.code.sf.net/p/host-sflow/code@482 c0bd136a-9412-4574-afac-2923e5188ea6
tagging release 1_26_1

git-svn-id: svn://svn.code.sf.net/p/host-sflow/code@483 c0bd136a-9412-4574-afac-2923e5188ea6