Python 3: Use 'filename: learnpython*.py' (no '3')

Before renaming, Python 3 filenames were 'learnpython3*.py'.

This commit removes the '3' part from the filename.

To verify that the filenames were named consistently across
translations prior to this commit, and to change this:

```
ack -H 'filename:' python.html.markdown
find . -name "python-*.markdown" -exec ack -H 'filename:' {} \;

sed -i 's/^filename: learnpython3/filename: learnpython/' \
  python.html.markdown

find . -name "python-*.markdown" -exec \
  sed -i 's/^filename: learnpython3/filename: learnpython/' {} \;
```

1 files changed, 1 insertions, 1 deletions

diff --git a/vi-vn/python-vi.html.markdown b/vi-vn/python-vi.html.markdown
index 58154f35..89e51d5d 100644
--- a/vi-vn/python-vi.html.markdown
+++ b/vi-vn/python-vi.html.markdown
@@ -1,6 +1,6 @@
 ---
 language: Python
-filename: learnpython3-vi.py
+filename: learnpython-vi.py
 contributors:
     - ["Louie Dinh", "http://pythonpracticeprojects.com"]
     - ["Steven Basart", "http://github.com/xksteven"]