Remove 4th unknown cam

Change-Id: I835ebd15b4d9bdb94c7298a6876954871c3d37d6
diff --git a/person_detection/config.py b/person_detection/config.py
index f31b769..ab510fa 100644
--- a/person_detection/config.py
+++ b/person_detection/config.py
@@ -3,4 +3,4 @@
 SPDX-License-Identifier: LicenseRef-ONF-Member-1.01
 """
 
-cameras = {"0": "Ain's desk", "1":"HungWei's desk", "2":"Shad's desk", "3":"Unknown"}
+cameras = {"0": "Ain's desk", "1":"HungWei's desk", "2":"Shad's desk"}