The SCM repositories have a "clean()" method to strip out the server's
own configuration files from the property sources shipped to remote
clients. The "native" one didn't have that method so this change adds
it with a similar implementation to the SCM case, except slightly
more complicated because of the extra search locations added by the
"label" parameter.
Also changes the name SpringApplicationEnvironmentRepository to
NativeEnvironmentRepository to match the profile and the config properties.
Fixes gh-109
b1ba8df066