Bug 582368: [Sirius][PropertiesView] Fix helpExpression on
CommunicationPath

From Properties VSM, helpExpression on feature ownedEnd of
CommunicationPath refers now to ownedEnd feature (instead of
navigableOwnedEnd).

Bug: https://bugs.eclipse.org/bugs/show_bug.cgi?id=582368
Change-Id: Ie0c1081796a6d6e6031dca41eaafd04cddd5bfc0
Signed-off-by: Jessy Mallet <jessy.mallet@obeo.fr>