Description of problem:
'dnf' dies with a traceback if "includeconf=<filename>" is used in
  a config file.
Also, "includeconf" is not documented in dnf.conf(5) or yum2dnf(8)
  (in yum it was named "include"; that name got repurposed in dnf).
Also, in conf/parser.py, there are still several references to the
  old name "include" (where "includeconf" is actually meant).

Version-Release number of selected component:
  python3-dnf-1.1.5-1.fc23.noarch (SRPM is dnf-1.1.5-1.fc23.src.rpm)

How reproducible:
100%

Steps to Reproduce:
1. echo "includeconf=/dev/null" > /tmp/dnf.conf.test
2. dnf -c /tmp/dnf.conf.test check-update
(The lack of contents in /dev/null makes no difference.)

To check documentation:
1. man -s5 dnf.conf | grep "includeconf"
2. man -s8 yum2dnf.conf | grep "includeconf"    # name change is an incompatibility

To check bogus references to "include":
1. grep -w "include" /usr/lib/python3.4/site-packages/dnf/conf/parser.py

Actual results:
Traceback (most recent call last):
  ...
  File "/usr/lib/python3.4/site-packages/dnf/conf/parser.py", line 236, in _popfile
    self.name = self._incstack[-1].geturl()
  File "/usr/lib64/python3.4/tempfile.py", line 394, in __getattr__
    a = getattr(file, name)
AttributeError: '_io.TextIOWrapper' object has no attribute 'geturl'

Expected results:
No traceback.
Some mention of includeconf in man pages.
conf/parser.py refers to "includeconf", not "include".