Fix print_function bug for python 2.5 as well.

IPython/core/magic.py

@@ -41,6 +41,11 b' except ImportError:'
     except ImportError:
         profile = pstats = None
 
+# print_function was added to __future__ in Python2.6, remove this when we drop
+# 2.5 compatibility
+if not hasattr(__future__,'CO_FUTURE_PRINT_FUNCTION'):
+    __future__.CO_FUTURE_PRINT_FUNCTION = 65536
+
 import IPython
 from IPython.core import debugger, oinspect
 from IPython.core.error import TryNext