Description: examples: fix unusual-interpreter v2

*Update in v2*
- use #!/usr/bin/env python as usually recommended and suggested in the
  discussion

Due to regular lintian checks in Debian packaging it surfaced that these
two scripts had a space in their #! statement which renders it to be
human, but not shell readable.

Fixes: 8673a3e8 ("examples/ip_pipeline: add config diagram generator")
Fixes: fa667b46 ("examples/ip_pipeline: add core mappings script")

This gets rid of lintian warning "W: dpdk-doc: unusual-interpreter"

Forwarded: yes
Author: Christian Ehrhardt <christian.ehrhardt@canonical.com>
Last-Update: 2016-08-02

--- a/examples/ip_pipeline/config/diagram-generator.py
+++ b/examples/ip_pipeline/config/diagram-generator.py
@@ -1,4 +1,4 @@
-#! /usr/bin/python2
+#!/usr/bin/env python
 
 #   BSD LICENSE
 #
--- a/examples/ip_pipeline/config/pipeline-to-core-mapping.py
+++ b/examples/ip_pipeline/config/pipeline-to-core-mapping.py
@@ -1,4 +1,4 @@
-#! /usr/bin/python2
+#!/usr/bin/env python
 
 #   BSD LICENSE
 #