Don't bother with multiple named repository lists for the targlet task
because there will be only one stream and it should always just use the
very recent versions of EMF and GEF.

The root Platform.setup in Oomph will manage the fixed value for the
eclipse.target.platform variable so that it only needs to be managed in
a single place in the future.

Change-Id: I18870f94dcc0c7afa8e122bd976e090212c74b3a
Signed-off-by: Ed Merks <ed.merks@gmail.com>