Explain ansible_python_interp. a little better

docsite/rst/patterns.rst

@@ -210,8 +210,8 @@ Tip: Keeping your inventory file and variables in a git repo (or other version c
 is an excellent way to track changes to your inventory and host variables.
 
 .. versionadded:: 0.5
-   If you ever have two python interpreters on a system, set a
-   variable called 'ansible_python_interpreter' to the Python
+   If you ever have two python interpreters on a system, or your Python version 2 interpreter is not found
+   at /usr/bin/python, set an inventory variable called 'ansible_python_interpreter' to the Python
    interpreter path you would like to use.
 
 .. seealso::