Tab completion (regression?)

I recently upgraded from 5.2.2 to 5.4.0. When I did, I started experiencing issues with my tab completion, particularly when trying to autocomplete paths. For example, if I hit [tab] at the end of a directory name, I no longer see a list of all the files in the directory. I get:


The files in the directory are listed, but they're buried in a long list of python objects. I haven't messed with this a lot, because I don't really know how to start debugging, but I did try reverting back to 5.2.2, which didn't help.

Also, I upgraded a lot of packages all at once through `conda upgrade --all`, so this could be a bug resulting from another upgrade. Here's the full output of `conda list --revisions`:

```
2018-02-06 11:31:34 (rev 20)
asn1crypto {0.23.0 -> 0.24.0}
bleach {2.1.1 -> 2.1.2}
cffi {1.11.2 -> 1.11.4}
cytoolz {0.8.2 -> 0.9.0}
decorator {4.1.2 -> 4.2.1}
html5lib {0.999999999 -> 1.0.1}
ipykernel {4.6.1 -> 4.8.0}
jedi {0.11.0 -> 0.11.1}
jupyter_client {5.1.0 -> 5.2.2}
jupyterlab {0.27.0 -> 0.31.2}
jupyterlab_launcher {0.4.0 -> 0.10.2}
mistune {0.8.1 -> 0.8.3}
notebook {5.2.2 -> 5.4.0}
numpy {1.13.3 -> 1.13.3}
parso {0.1.0 -> 0.1.1}
pexpect {4.3.0 -> 4.3.1}
python {3.6.3 -> 3.6.4}
ruamel_yaml {0.11.14 -> 0.15.35}
setuptools {36.5.0 -> 38.4.0}
sqlite {3.20.1 -> 3.22.0}
terminado {0.6 -> 0.8.1}
toolz {0.8.2 -> 0.9.0}
tornado {4.5.2 -> 4.5.3}
+send2trash-1.4.2
```

Any thoughts?