Fix #18515: Don't fail in DEBUG mode

When no Redis server is reachable management commands failed without
this try...except block.

Author: tobiasge

netbox/core/apps.py

@@ -28,4 +28,7 @@ def ready(self):
 
         # Clear Redis cache on startup in development mode
         if settings.DEBUG:
-            cache.clear()
+            try:
+                cache.clear()
+            except Exception:
+                pass