Drop support for Python 2.5

repo will soon be dropping support for Python 2.5.  This change
updates our docs to reflect that.

Change-Id: I86dc8da2f62efcce2e84f1c9a11f864b95e238d7
diff --git a/src/source/initializing.md b/src/source/initializing.md
index ac50857..ed98b99 100644
--- a/src/source/initializing.md
+++ b/src/source/initializing.md
@@ -56,7 +56,7 @@
 
 Detailed instructions for Ubuntu and MacOS follow. In general you will need:
 
- - Python 2.5 -- 2.7, which you can download from [python.org](http://www.python.org/download/).
+ - Python 2.6 -- 2.7, which you can download from [python.org](http://www.python.org/download/).
 
  - GNU Make 3.81 -- 3.82, which you can download from [gnu.org](http://ftp.gnu.org/gnu/make/),