puppet-compare: provision python-dev

The python installation of markupsafe yields:

markupsafe/_speedups.c:12:20: fatal error: Python.h: No such file or
directory
compilation terminated.
==========================================================================
WARNING: The C extension could not be compiled, speedups are not
enabled.
Failure information, if any, is above.
Retrying the build without the C extension now.

I guess installing python-dev would fix it.

Change-Id: I1c76df7282c3e3e4f385d6be31beafd9fbda2526