Fix 'UnicodeEncodeError' for unicode values

Used '%' instead of format() because "%" formatting operation
returns a unicode string for both unicode and non-unicode
format strings.

Encoded the exception error message in novaclient.shell.main and
novaclient.utils.do_action_on_many method to avoid
"UnicodeEncodeError" and print valid message.

NOTE:
Not used u'{0}.format(<str>) because in python 3 everything
is unicode so no need to add explicit 'u' to format string.

Closes-Bug: #1403379
Change-Id: I13f1ef2e1b41299b417cad3759a5cda241890df7
3 files changed