jobctrl: use shell if the command line has shell control chars (|><), so that "bzr log | less" etc. work

IPython/Extensions/jobctrl.py

@@ -199,7 +199,7 b' def jobctrl_shellcmd(ip,cmd):'
     """ os.system replacement that stores process info to db['tasks/t1234'] """
     cmd = cmd.strip()
     cmdname = cmd.split(None,1)[0]
-    if cmdname in shell_internal_commands:
+    if cmdname in shell_internal_commands or '|' in cmd or '>' in cmd or '<' in cmd:
         use_shell = True
     else:
         use_shell = False