main/coreplugin: use log.exception() instead of traceback.print_exc()

This fixes tracebacks only being sent to console, and not the log file.

coreplugin.py

@@ -1,7 +1,5 @@
 ## coreplugin.py - Core PyLink plugin
 
-import traceback
-
 import utils
 from log import log
 
@@ -33,7 +31,7 @@ def handle_commands(irc, source, command, args):
         try:
             func(irc, source, cmd_args)
         except Exception as e:
-            traceback.print_exc()
+            log.exception('Unhandled exception caught in command %r' % cmd)
             utils.msg(irc, source, 'Uncaught exception in command %r: %s: %s' % (cmd, type(e).__name__, str(e)))
             return
 utils.add_hook(handle_commands, 'PRIVMSG')

main.py

@@ -7,7 +7,6 @@ import time
 import sys
 from collections import defaultdict
 import threading
-import traceback
 
 from log import log
 import conf
@@ -152,7 +151,7 @@ class Irc():
                 hook_func(self, numeric, command, parsed_args)
             except Exception:
                 # We don't want plugins to crash our servers...
-                traceback.print_exc()
+                log.exception('Unhandled exception caught in %r' % hook_func)
                 continue
 
     def send(self, data):