Add checks to Python scripts for version dependencies.

Signed-off-by: Eric S. Raymond <esr@thyrsus.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

git_remote_helpers/git/__init__.py

@@ -0,0 +1,5 @@
+import sys
+if sys.hexversion < 0x02040000:
+    # The limiter is the subprocess module
+    sys.stderr.write("git_remote_helpers: requires Python 2.4 or later.\n")
+    sys.exit(1)