This commit adds the ability to specify a plugin from maven for a
test cluster to use. Currently, only local projects may be used as
plugins, except when testing bwc, where the coordinates of the project
are used. However, that assumes all projects always keep the same
coordinates, or are even still plugins, which is no longer the case for
x-pack. The full cluster and rolling restart tests are changed to use
this new method when pulling x-pack versions before 6.3.0.
This commit makes x-pack a module and adds it to the default
distrubtion. It also creates distributions for zip, tar, deb and rpm
which contain only oss code.
Ryan Ernst
Jason Tedor