python3: fix multiprocessing module bug with serialization

Part of #265

Author: ligurio

dispatcher.py

@@ -82,6 +82,13 @@ class Dispatcher:
     ```
     """
     def __init__(self, task_groups, max_workers_cnt, randomize):
+        """
+        try:
+            # Python 3
+            multiprocessing.set_start_method('fork')
+        except AttributeError:
+            pass
+        """
         self.pids = []
         self.processes = []
         self.result_queues = []

lib/test_suite.py

@@ -120,10 +120,10 @@ def __init__(self, suite_path, args):
             self.ini[i] = dict.fromkeys(self.ini[i].split()) \
                 if i in self.ini else dict()
         for i in ["lua_libs"]:
-            self.ini[i] = map(
-                lambda x: os.path.join(suite_path, x),
-                dict.fromkeys(self.ini[i].split())
-                if i in self.ini else dict())
+            lua_libs = self.ini.get(i, "")
+            self.ini[i] = []
+            for p in lua_libs.split():
+                self.ini[i].append(os.path.join(suite_path, p))
         if config.has_option("default", "fragile"):
             fragiles = config.get("default", "fragile")
             try: