Ruby: Add new object called WireBuffer to mimic a Wire.

This is a substitute for MessageBuffers between controllers where you don't
want messages to actually go through the Network, because requests/responses can
always get reordered wrt to one another (even if you turn off Randomization and turn on Ordered)
because you are, after all, going through a network with contention. For systems where you model
multiple controllers that are very tightly coupled and do not actually go through a network,
it is a pain to have to write a coherence protocol to account for mixed up request/response orderings
despite the fact that it's completely unrealistic.  This is *not* meant as a substitute for real
MessageBuffers when messages do in fact go over a network.

src/mem/ruby/SConscript

@@ -107,6 +107,7 @@ MakeInclude('system/DMASequencer.hh')
 MakeInclude('system/DirectoryMemory.hh')
 MakeInclude('system/MachineID.hh')
 MakeInclude('system/MemoryControl.hh')
+MakeInclude('system/WireBuffer.hh')
 MakeInclude('system/NodeID.hh')
 MakeInclude('system/PerfectCacheMemory.hh')
 MakeInclude('system/PersistentTable.hh')