lttng2: Update lttng2 feature dependency to require RSE feature

lttng2: Update lttng2 feature dependency to require RSE feature

The lttng2 feature now requires the feature Remote System Explorer
End-User Runtime (org.eclipse.rse) instead of certain RSE plug-ins.
This causes p2 to automatically install the all necessary RSE
features (e.g. ssh shell) features needed by lttng2. Before this
commit the RSE runtime feature had to be installed manually.

Change-Id: I39dc6baaf161047cbd44b7a87bbd78e8631caad7
Signed-off-by: Bernd Hufmann <Bernd.Hufmann@ericsson.com>
Reviewed-on: https://git.eclipse.org/r/12413
Tested-by: Hudson CI
Reviewed-by: Alexandre Montplaisir <alexmonthy@voxpopuli.im>
IP-Clean: Alexandre Montplaisir <alexmonthy@voxpopuli.im>
Tested-by: Alexandre Montplaisir <alexmonthy@voxpopuli.im>
Reviewed-by: Marc-Andre Laperle <marc-andre.laperle@ericsson.com>
Reviewed-by: Bernd Hufmann <bernd.hufmann@ericsson.com>
Tested-by: Bernd Hufmann <bernd.hufmann@ericsson.com>