Tweak description of failure.

IPython/core/magic.py

@@ -954,7 +954,7 b' Currently the magic system has the following functions:\\n"""'
                     vstr = unicode(var).encode(DEFAULT_ENCODING,
                                                'backslashreplace')
                 except:
-                    vstr = "<object with id %d (repr failed)>" % id(var)
+                    vstr = "<object with id %d (str() failed)>" % id(var)
                 vstr = vstr.replace('\n','\\n')
                 if len(vstr) < 50:
                     print vstr