Installing backend requirements fails because "httplib" cannot be found in PIP

[wetneb]

Downloading/unpacking httplib (from -r requirements_backend.txt (line 6))
  Could not find any downloads that satisfy the requirement httplib (from -r requirements_backend.txt (line 6))
  Some externally hosted files were ignored (use --allow-external httplib to allow).
Cleaning up...
No distributions at all found for httplib (from -r requirements_backend.txt (line 6))
Traceback (most recent call last):
  File "/home/a3nm/scratch/dissemin/.virtualenv/bin/pip", line 11, in 
    sys.exit(main())
  File "/home/a3nm/scratch/dissemin/.virtualenv/local/lib/python2.7/site-packages/pip/__init__.py", line 248, in main
    return command.main(cmd_args)
  File "/home/a3nm/scratch/dissemin/.virtualenv/local/lib/python2.7/site-packages/pip/basecommand.py", line 161, in main
    text = '\n'.join(complete_log)
UnicodeDecodeError: 'ascii' codec can't decode byte 0xe2 in position 72: ordinal not in range(128)