Remove 'next_url' from kwargs before passing it to the cls constructor.

The 'next_url' argument causes problems in the _construct_url method if it
doesn't belong there. E.g. if you list all projects, change an attribute
of a project and then try to save it, the _construct_url will use the
'next_url' from the list method and the save will fail.

gitlab/__init__.py

@@ -281,7 +281,7 @@ def _raw_list(self, path, cls, **kwargs):
         get_all_results = kwargs.get('all', False)
 
         # Remove parameters from kwargs before passing it to constructor
-        for key in ['all', 'page', 'per_page', 'sudo']:
+        for key in ['all', 'page', 'per_page', 'sudo', 'next_url']:
             if key in cls_kwargs:
                 del cls_kwargs[key]
 
@@ -385,7 +385,7 @@ def list(self, obj_class, **kwargs):
         get_all_results = params.get('all', False)
 
         # Remove parameters from kwargs before passing it to constructor
-        for key in ['all', 'page', 'per_page', 'sudo']:
+        for key in ['all', 'page', 'per_page', 'sudo', 'next_url']:
             if key in cls_kwargs:
                 del cls_kwargs[key]