make local group manipulation instance methods

src/python/dm/common/utility/ldapLinuxPlatformUtility.py

@@ -213,15 +213,13 @@ class LdapLinuxPlatformUtility:
         cmd = '%s %s' % (cls.GROUPADD_CMD, name)
         cls.executeSudoCommand(cmd)
 
-    @classmethod
-    def addLocalUserToGroup(cls, username, groupName):
+    def addLocalUserToGroup(self, username, groupName):
         """ Add local user to group. """
-        cls.addUserToGroup(username, groupName)
+        self.addUserToGroup(username, groupName)
 
-    @classmethod
-    def deleteLocalUserFromGroup(cls, username, groupName):
+    def deleteLocalUserFromGroup(self, username, groupName):
         """ Remove local user from group. """
-        cls.deleteUserFromGroup(username, groupName)
+        self.deleteUserFromGroup(username, groupName)
 
     def getGroupInfo(self, groupName):
         """ Get given group info. """