Crashes when doing cron.daily indexing

[Marsh]

/etc/cron.daily/apt:
Traceback (most recent call last):
  File "/usr/sbin/update-apt-xapian-index", line 101, in <module>
    if not indexer.setupIndexing(force=opts.force, system=opts.pkgfile is None):
  File "/usr/lib/python2.7/dist-packages/axi/indexer.py", line 471, in setupIndexing
    self.plugins = Plugins(progress=self.progress, system=system)
  File "/usr/lib/python2.7/dist-packages/axi/indexer.py", line 94, in __init__
    addon = Addon(fullname, **kw)
  File "/usr/lib/python2.7/dist-packages/axi/indexer.py", line 49, in __init__
    self.module = imp.load_source("axi.plugin_" + self.name, fname)
  File "/usr/share/apt-xapian-index/plugins/software_center.py", line 13, in <module>
    from softwarecenter.db.update import (
  File "/usr/share/software-center/softwarecenter/db/update.py", line 31, in <module>
    from piston_mini_client import PistonResponseObject
  File "/usr/lib/python2.7/dist-packages/piston_mini_client/__init__.py", line 65, in <module>
    from httplib2 import _md5, re_url_scheme, re_slash
ImportError: cannot import name re_slash

ProblemType: Bug
DistroRelease: Ubuntu 14.04
Package: apt-xapian-index 0.45ubuntu4
ProcVersionSignature: Ubuntu 3.13.0-166.216-generic 3.13.11-ckt39
Uname: Linux 3.13.0-166-generic x86_64
NonfreeKernelModules: nvidia
ApportVersion: 2.14.1-0ubuntu3.29
Architecture: amd64
Date: Thu Mar 7 15:43:11 2019
PackageArchitecture: all
ProcEnviron:
 LANGUAGE=en_US:en
 TERM=xterm
 PATH=(custom, no user)
 LANG=C
 SHELL=/bin/bash
SourcePackage: apt-xapian-index
UpgradeStatus: Upgraded to trusty on 2016-06-09 (1001 days ago)

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.