There are some functions in novaclient/utils.py which have name with
prefix `_`, in Python, this means it is a private function which
should be only used in its own module. However, these functions are
used in other modules such as novaclient/v2/shell.py.
This patch removes the prefix _ for these functions.
Change-Id: I7bc8a76fd390a7dd30eecbb5c7e641b6ccfb40c0