foo.diff

diff --git a/django/utils/version.py b/django/utils/version.py
index c680dbd..90a41ad 100644
--- a/django/utils/version.py
+++ b/django/utils/version.py
@@ -57,6 +57,10 @@ def get_git_changeset():
     This value isn't guaranteed to be unique, but collisions are very unlikely,
     so it's sufficient for generating the development version numbers.
     """
+    # FIXME: Replace with @lru_cache when we upgrade the docs server to PY2.7+.
+    if hasattr(get_git_changeset, 'cache'):
+        return get_git_changeset.cache
+
     repo_dir = os.path.dirname(os.path.dirname(os.path.abspath(__file__)))
     git_log = subprocess.Popen('git log --pretty=format:%ct --quiet -1 HEAD',
             stdout=subprocess.PIPE, stderr=subprocess.PIPE,
@@ -65,5 +69,9 @@ def get_git_changeset():
     try:
         timestamp = datetime.datetime.utcfromtimestamp(int(timestamp))
     except ValueError:
-        return None
-    return timestamp.strftime('%Y%m%d%H%M%S')
+        changeset = None
+    else:
+        changeset = timestamp.strftime('%Y%m%d%H%M%S')
+
+    get_git_changeset.cache = changeset
+    return changeset