fix issue with plugin load path inconsistency

now assures it is always a list of paths and not just assumes it
this avoids issues of parsing a 'string path' and picking up '/' as
a valid path for plugin loader

lib/ansible/plugins/__init__.py

@@ -61,10 +61,14 @@ class PluginLoader:
         self.class_name         = class_name
         self.base_class         = required_base_class
         self.package            = package
-        self.config             = config
         self.subdir             = subdir
         self.aliases            = aliases
 
+        if not isinstance(config, list):
+            config = [config]
+
+        self.config = config
+
         if not class_name in MODULE_CACHE:
             MODULE_CACHE[class_name] = {}
         if not class_name in PATH_CACHE: