ruby: Fix regressions and make Ruby configs Python packages

This patch moves the addition of network options into the Ruby module
to avoid the regressions all having to add it explicitly. Doing this
exposes an issue in our current config system though, namely the fact
that addtoPath is relative to the Python script being executed. Since
both example and regression scripts use the Ruby module we would end
up with two different (relative) paths being added. Instead we take a
first step at turning the config modules into Python packages, simply
by adding a __init__.py in the configs/ruby, configs/topologies and
configs/network subdirectories.

As a result, we can now add the top-level configs directory to the
Python search path, and then use the package names in the various
modules. The example scripts are also updated, and the messy
path-deducing variations in the scripts are unified.

configs/ruby/Ruby.py

@@ -46,10 +46,9 @@ from m5.defines import buildEnv
 from m5.util import addToPath, fatal
 
 import MemConfig
-addToPath('../topologies')
-addToPath('../network')
 
-import Network
+from topologies import *
+from network import Network
 
 def define_options(parser):
     # By default, ruby uses the simple timing cpu
@@ -80,6 +79,7 @@ def define_options(parser):
     protocol = buildEnv['PROTOCOL']
     exec "import %s" % protocol
     eval("%s.define_options(parser)" % protocol)
+    Network.define_options(parser)
 
 def setup_memory_controllers(system, ruby, dir_cntrls, options):
     ruby.block_size_bytes = options.cacheline_size
@@ -141,7 +141,7 @@ def create_topology(controllers, options):
         found in configs/topologies/BaseTopology.py
         This is a wrapper for the legacy topologies.
     """
-    exec "import %s as Topo" % options.topology
+    exec "import topologies.%s as Topo" % options.topology
     topology = eval("Topo.%s(controllers)" % options.topology)
     return topology