Fix option for upgrade mysql

Change-Id: Ibba71d4275d4bc6252e2125b9497469e1eabcbb8
diff --git a/tcp_tests/tests/system/conftest.py b/tcp_tests/tests/system/conftest.py
index 74b3ea3..8badb8f 100644
--- a/tcp_tests/tests/system/conftest.py
+++ b/tcp_tests/tests/system/conftest.py
@@ -84,7 +84,10 @@
 
 def pytest_addoption(parser):
     parser.addoption("--update-to-tag",
-                     "--update-mysql-version",
                      action="store",
                      default=None,
                      help="For mcp_update test")
+    parser.addoption("--update-mysql-version",
+                     action="store",
+                     default=None,
+                     help="For update mysql test")