Fixed Content-Type retrieval for Python 3.

httpie/downloads.py

@@ -116,6 +116,9 @@ def filename_from_url(url, content_type):
         else:
             ext = mimetypes.guess_extension(content_type)
 
+        if ext == '.htm':  # Python 3
+            ext = '.html'
+
         if ext:
             fn += ext
 

httpie/models.py

@@ -87,7 +87,13 @@ class HTTPMessage(object):
     @property
     def content_type(self):
         """Return the message content type."""
-        ct = self._orig.headers.get('Content-Type', '')
+        ct = self._orig.headers.get(
+            b'Content-Type',
+            self._orig.headers.get(
+                'Content-Type',
+                ''
+            )
+        )
         if isinstance(ct, bytes):
             ct = ct.decode()
         return ct