This is more flexible regarding the location of the python binary
but doesn't allow to pass the -u flag. The -i flag can be passed
from inside the script using the PYTHONINSPECT env variable.

This fixes a problem with the esx_vi_generator.py on FreeBSD.

It also demonstrates how to use the libvirt.openAuth() method.

* examples/python/Makefile.am: add esxlist.py to EXTRA_DIST
* examples/python/README: add some notes about esxlist.py
* examples/python/esxlist.py: the new example