Rename instance_type to flavor in vmware virt driver tests

Renames 'instance_type' to 'flavor' in the vmware virt driver tests.
There were no occurrences of 'instance_type' in the virt driver itself,
so this patch only changes the tests.

Part of blueprint flavor-instance-type-dedup

Change-Id: I81ea543e0ab480e35cf5b7b59bd9ecb1cf361c6f
Sync processutils from oslo-incubator

This includes the following changes:

  af41592 Catch OSError in processutils
  f773ea2 Fix i18n problem in processutils module
  8b2b0b7 Use hacking import_exceptions for gettextutils._
  3b71f46 Fixed misspellings of common words
  12bcdb7 Remove vim header
  a4dab73 Correct execute() to check 0 in check_exit_code

Closes-bug: #1271331
Change-Id: I12b621fa5a2cdeeab6d51902416ce5dd4db61ba7
Merge "Sync processutils from oslo-incubator"
Merge "Rename instance_type to flavor in vmware virt driver tests"