All Python files, except executables, should have a '.py' extension.
This wasn't being done for files in the 'plugins/xenserver' folder,
likely because it seems unnatural to call a "plugin" with a file
extension.
Begin working towards a resolution for this by renaming all files to
include a '.py' extension. To avoid forcing operators to upgrade the
Nova service and per-host plugins at the same time, continue to
reference the old, non-'.py' filenames, using symlinks to ensure the
references continue to work. Once Ocata has been released, these
symlinks can be removed, the API version updated and the reference
updated to include the '.py' extension.
Change-Id: Icf4cf2424c15276a6c01778fb92f76bbdc9b2068
Closes-bug: #1302831
6bb1fd776f