Fixed visibility parameter for create package glare call

When creating a murano-package artifact in Glare muranoclient was not
properly passing the visibility parameter. Instead, it was passing the
'is_public' parameter, which is not supported by Glare.

Appropriate conversion has been added to PackageManagerAdapter class

Change-Id: Ia3a038d2b16e27effd208f5e4877f1f06d8ad882
Closes-bug: #1537018

muranoclient/v1/artifact_packages.py

@@ -207,6 +207,9 @@ class PackageManagerAdapter(object):
 
     @rewrap_http_exceptions
     def create(self, data, files):
+        is_public = data.pop('is_public', None)
+        if is_public is not None:
+            data['visibility'] = 'public' if is_public else 'private'
         fqn = list(files.keys())[0]
         pkg = self.glare.create(fqn, files[fqn], **data)
         return PackageWrapper(pkg)