osc-origin, osclib/origin: port first dict key/value access [python3].

osc-origin.py

@@ -131,7 +131,7 @@ def osrt_origin_lookup(apiurl, project, force_refresh=False, previous=False, qui
         with open(lookup_path, 'r') as lookup_stream:
             lookup = yaml.safe_load(lookup_stream)
 
-            if not isinstance(lookup.itervalues().next(), dict):
+            if not isinstance(next(iter(lookup.values())), dict):
                 # Convert flat format to dictionary.
                 for package, origin in lookup.items():
                     lookup[package] = {'origin': origin}

osclib/origin.py

@@ -86,7 +86,7 @@ def config_resolve(apiurl, project, config):
     origins = config['origins']
     i = 0
     while i < len(origins):
-        origin = origins[i].keys()[0]
+        origin = next(iter(origins[i]))
         values = origins[i][origin]
 
         if origin == '*':