wheezy: is_hop_by_hop has been removed from Django

Implement our own is_hop_by_hop function.

snf-django-lib/snf_django/lib/api/proxy/utils.py

@@ -31,7 +31,19 @@
 # interpreted as representing official policies, either expressed
 # or implied, of GRNET S.A.
 
-from django.core.servers.basehttp import is_hop_by_hop
+try:
+    from django.core.servers.basehttp import is_hop_by_hop
+except ImportError:
+    # Removed in Django 1.4
+    _hop_headers = {
+        'connection': 1, 'keep-alive': 1, 'proxy-authenticate': 1,
+        'proxy-authorization': 1, 'te': 1, 'trailers': 1,
+        'transfer-encoding': 1, 'upgrade': 1
+    }
+
+    def is_hop_by_hop(header_name):
+        """Return true if 'header_name' is an HTTP/1.1 "Hop-by-Hop" header"""
+        return header_name.lower() in _hop_headers
 
 
 def fix_header(k, v):
@@ -43,4 +55,4 @@ def fix_header(k, v):
 
 def forward_header(k):
     return k.upper() not in ['HOST', 'CONTENT_LENGTH', 'CONTENT_TYPE'] and \
-           not is_hop_by_hop(k) and not '.' in k
+        not is_hop_by_hop(k) and not '.' in k