re-seed the Python random number generator after forking jobs

At some point during pyres_worker startup, the Python PRNG is
seeded. Since pyres_worker doesn't generate any random numbers on
its own, each job process that is forked starts with the PRNG in
the same state.

Fixes binarymatt#82
binarymatt#82

Author: Peter Teichman

pyres/worker.py

@@ -4,6 +4,7 @@
 import os, sys
 import json_parser as json
 import commands
+import random
 
 from pyres.exceptions import NoQueueError
 from pyres.job import Job
@@ -167,6 +168,12 @@ def work(self, interval=5):
                     logger.info('Processing %s since %s' %
                                  (job._queue, datetime.datetime.now()))
                     self.after_fork(job)
+
+                    # re-seed the Python PRNG after forking, otherwise
+                    # all job process will share the same sequence of
+                    # random numbers
+                    random.seed()
+
                     self.process(job)
                     os._exit(0)
                 self.child = None