Removes the py24 requirements file now that 2.4 is no longer supported

requirements/README.rst

@@ -16,7 +16,7 @@ Index
 
 * `requirements/py26.txt`
 
-    Extra requirements needed to run on Python 2.4.
+    Extra requirements needed to run on Python 2.6.
 
 * `requirements/test.txt`
 

requirements/py24.txt

@@ -1,4 +0,0 @@
-uuid
-importlib
-multiprocessing==2.6.2.1
-pysqlite