Change 'filename:' for Python 2 (legacy)

Before renaming, all Python 2 filenames were 'learnpython-*.py'.

This commit renames them to 'learnpythonlegacy-*.py'.

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

```
find . -name "pythonlegacy*.markdown" -exec ack filename: {} \;

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

1 files changed, 1 insertions, 1 deletions

diff --git a/pythonlegacy.html.markdown b/pythonlegacy.html.markdown
index 25c22f78..95d6aa63 100644
--- a/pythonlegacy.html.markdown
+++ b/pythonlegacy.html.markdown
@@ -8,7 +8,7 @@ contributors:
     - ["asyne", "https://github.com/justblah"]
     - ["habi", "http://github.com/habi"]
     - ["Rommel Martinez", "https://ebzzry.io"]
-filename: learnpython.py
+filename: learnpythonlegacy.py
 ---
 
 Python was created by Guido Van Rossum in the early 90s. It is now one of the