Remove all unused variables.

third_party/WebKit/Tools/Scripts/webkitpy/common/message_pool.py

Index: third_party/WebKit/Tools/Scripts/webkitpy/common/message_pool.py
diff --git a/third_party/WebKit/Tools/Scripts/webkitpy/common/message_pool.py b/third_party/WebKit/Tools/Scripts/webkitpy/common/message_pool.py
index 3dfe3b723a33f9982f644f46a59898b19e91ea66..2edd7e2f25a10a68c1deadbdc5966001c66e9374 100644
--- a/third_party/WebKit/Tools/Scripts/webkitpy/common/message_pool.py
+++ b/third_party/WebKit/Tools/Scripts/webkitpy/common/message_pool.py
@@ -246,7 +246,6 @@ class _Worker(multiprocessing.Process):
             self._set_up_logging()
 
         worker = self._worker
-        exception_msg = ""
         _log.debug("%s starting" % self.name)
         self._running = True
 
@@ -265,9 +264,9 @@ class _Worker(multiprocessing.Process):
             _log.debug("%s exiting" % self.name)
         except Queue.Empty:
             assert False, '%s: ran out of messages in worker queue.' % self.name
-        except KeyboardInterrupt as e:
+        except KeyboardInterrupt:
             self._raise(sys.exc_info())
-        except Exception as e:
+        except Exception:
             self._raise(sys.exc_info())
         finally:
             try: