Set rw-core tag to 3.6.4 for Berlin lab deployment

The tests were failing with the newest master version of the rw-core
image, so the tag is set to a previously working one so they can be
debugged further.

Signed-off-by: Cristina de Francisco <cristina.defrancisco@bisdn.de>
Change-Id: I3558634dafe97dd284af86ba3303e3d0dbdcd817
7 files changed