Backport PR
#2169: ipdb: pdef, pdoc, pinfo magics all broken...
Backport PR
#2169: ipdb: pdef, pdoc, pinfo magics all broken
```
In[1]: dg.meshes.square.qmesh(2)
...
IndexError: index (48) out of range (0<=index<47) in dimension 0
In [2]: debug
...
ipdb> pinfo jx
...
/usr/lib/python2.7/dist-packages/IPython/core/debugger.pyc in do_pinfo(self, arg)
490 namespaces = [('Locals', self.curframe.f_locals),
491 ('Globals', self.curframe.f_globals)]
--> 492 self.shell.magic_pinfo("pinfo %s" % arg, namespaces=namespaces)
493
494 def checkline(self, filename, lineno):
AttributeError: 'TerminalInteractiveShell' object has no attribute 'magic_pinfo'
```
