Description:
Conversion to epub fails

Additional info:
* package version: 2.15.0-1

Steps to reproduce:
1) Have a book in .epub format only.
2) Try to put it onto a kindle.

I get a popup error with the following text:

Convert book 1 of 1 (Rogues)
Traceback (most recent call last):
File "/usr/bin/calibre-parallel", line 20, in <module>
sys.exit(main())
File "/usr/lib/calibre/calibre/utils/ipc/worker.py", line 193, in main
result = func(*args, **kwargs)
File "/usr/lib/calibre/calibre/gui2/convert/gui_conversion.py", line 31, in gui_convert_override
override_input_metadata=True)
File "/usr/lib/calibre/calibre/gui2/convert/gui_conversion.py", line 25, in gui_convert
plumber.run()
File "/usr/lib/calibre/calibre/ebooks/conversion/plumber.py", line 990, in run
self.setup_options()
File "/usr/lib/calibre/calibre/ebooks/conversion/plumber.py", line 939, in setup_options
self.read_user_metadata()
File "/usr/lib/calibre/calibre/ebooks/conversion/plumber.py", line 899, in read_user_metadata
os.path.dirname(self.opts.read_metadata_from_opf))
File "/usr/lib/calibre/calibre/ebooks/metadata/opf2.py", line 573, in __init__
resolve_entities=True, assume_utf8=True)
File "/usr/lib/calibre/calibre/ebooks/chardet.py", line 135, in xml_to_unicode
raw = substitute_entites(raw)
File "/usr/lib/calibre/calibre/ebooks/chardet.py", line 56, in substitute_entites
return ENTITY_PATTERN.sub(xml_entity_to_unicode, raw)
File "/usr/lib/calibre/calibre/__init__.py", line 579, in entity_to_unicode
from calibre.ebooks.html_entities import html5_entities
File "/usr/lib/calibre/calibre/ebooks/html_entities.py", line 9, in <module>
from html5lib.constants import entities
File "/usr/lib/python2.7/site-packages/html5lib/__init__.py", line 16, in <module>
from .html5parser import HTMLParser, parse, parseFragment
File "/usr/lib/python2.7/site-packages/html5lib/html5parser.py", line 6, in <module>
from . import inputstream
File "/usr/lib/python2.7/site-packages/html5lib/inputstream.py", line 3, in <module>
from six.moves import http_client
ImportError: No module named moves



The offending line is
"from six.moves import http_client"
Running python2 test.php on a file with that line gives the same error:
t@h ~> python2 test.py
Traceback (most recent call last):
File "test.py", line 1, in <module>
from six.moves import http_client
ImportError: No module named moves


The file /usr/lib/python2.7/site-packages/six/six.py on my system does contain the line
"moves = sys.modules[__name__ + ".moves"] = _MovedItems(__name__ + ".moves")"
which seems reasonable to me, but I don't know enough python to be sure.

python2-six is version 1.8.0-1 on my system.