Propertly implemented stubs for NewLaunchConfigEditPage

This code is required if any LaunchTab interacts with other tabs in LC


Change-Id: I5d5e3b6d4e51b1f3ee0ac6297ebb4d88ad220224
Signed-off-by: Alena Laskavaia <elaskavaia.cdt@gmail.com>
Reviewed-on: https://git.eclipse.org/r/36955
Tested-by: Hudson CI