dsynth - More pkg dependency fixes
* Fix the depency check based on the depth when recursing through a
dummy node. Dummy nodes do not increment the depth.
* In addition, recursing through a dummy node means that the package
only depends on the default flavor, which is only the first element
in the idepon list under that dummy node. Inform the next layer
that its scan should only iterate one element.
* In addition, when build_find_leaves() recurses through a dummy node
also use the same mechanism where only the first sub-node is
checked, because the dependency is (again) against just the default
flavor.
Note that when doing a 'dsynth everything', all the dependencies
wind up in the root list, so all the flavors get built. But when
building a specific subset of packages, this fix will reduce the
number of flavors that have to be built as dependencies.
UnifiedSplitRaw
