Match against entry_point origins using both package name and package name plus version. If one of those matches (depends on pip version if output will include version or not), it's the plugin we are looking for.
This way we don't need to try to strip a version number from the package name as output by pip without knowing if a version number is included or not.
Some pip invocations return extra info after the Successfully installed
(like "Cleaning up..."). Also, not all packages include a version
number in their package names.
