The nm-rdisc subsystem, just as the nm-platform subsystem is separately
testable and it proved convenient to be able to build the test programs
by just typing 'make' in the rdisc/platform directory where the source
code for those modules resides.
src/rdisc doesn't need a makefile just to point to the tests,
we can do that more easily from src/Makefile.am like we do for
all the other tests subdirs.
Abstract class, fake implementation and a manual testing tool for
NetworkManager's internal IPv6 router discovery module. When a real
implementation is ready, it will replace nm-ip6-manager and will be used
by nm-device.
