* stable-4.9:
Ignore API warnings
Fix photon target platform to use photon version of org.eclipse.osgi
Update Photon orbit repository to R20180606145124
Suppress warning for trying to delete non-empty directory
Fix fetching with duplicate ref updates
Fetch(Process): should tolerate duplicate refspecs
FetchCommandTest: test add/update/delete fetch
Change-Id: I2a83c059b7014c2a9e6267c963422c7785b23f17
Signed-off-by: Matthias Sohn <matthias.sohn@sap.com>