Additional Python 2.7 cleanups

Signed-off-by: Stephen Finucane <stephen@that.guru>

Author: stephenfin

README.rst

@@ -39,7 +39,7 @@ Requirements
 
 Patchwork requires reasonably recent versions of:
 
-- Python (2 or 3)
+- Python 3
 
 - Django
 

docs/deployment/installation.rst

@@ -44,9 +44,7 @@ Requirements
 For the purpose of this guide, we will assume an **Ubuntu 18.04** host:
 commands, package names and/or package versions will likely change if using a
 different distro or release. Similarly, usage of different package versions to
-the ones suggested may require slightly different configuration. For example,
-this guide describes configuration with **Python 3** and using Python 2 will
-require different packages and some minor changes to configuration files.
+the ones suggested may require slightly different configuration.
 
 Before beginning, you should update and restart this system:
 

patchwork/parser.py

@@ -765,11 +765,7 @@ def clean_content(content):
     """Remove cruft from the email message.
 
     Catch signature (-- ) and list footer (_____) cruft.
-
-    Change to Unix line endings (the Python 3 email module does this for us,
-    but not Python 2).
     """
-    content = content.replace('\r\n', '\n')
     sig_re = re.compile(r'^(-- |_+)\n.*', re.S | re.M)
     content = sig_re.sub('', content)