Description of problem:
I just diagnosed a build failure with sympy on python3.  Through a long chain of imports, it ultimately tries to import some python3-dateutil modules, but the import fails because python3-six is not in the build root.

$ cd /usr/lib/python3.4/site-packages/dateutil
$ grep six *.py
tz.py:from six import string_types, PY3
tz.py:        # sixteen bytes reserved for future use, followed by
tz.py:        # six four-byte values of type long, written in a
rrule.py:from six import advance_iterator, integer_types
parser.py:from six import text_type, binary_type, integer_types
relativedelta.py:from six import integer_types

python3-dateutil should have "Requires: python3-six" so these imports will succeed.

Version-Release number of selected component (if applicable):
python3-dateutil-2.2-1.fc22.noarch

How reproducible:
Always.

Steps to Reproduce:
1. Install python3-dateutil on a Rawhide machine that does not have python3-six installed.
2. Run python3
3. import dateutil.tz

Actual results:
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/usr/lib/python3.4/site-packages/dateutil/tz.py", line 9, in <module>
    from six import string_types, PY3
ImportError: No module named 'six'

Expected results:
Successful import.

Additional info:
The python2 version, python-dateutil, does not have the same problem.