dashboard crash if we have system plugin but not argonaut plugin in FD 1.3

Description

Hello,

Dashboard crash if we have system plugin without argonaut plugin in FD 1.3

Fatal error: Uncaught exception 'FusionDirectoryException' with message 'Could not find ACL for attribute "argonautProtocol"' in /usr/share/fusiondirectory/include/class_objects.inc:90 Stack trace: #0 /usr/share/fusiondirectory/plugins/addons/dashboard/class_dashBoardSystems.inc(137): objects::ls('server', Array, NULL, '(objectClass=ar...', true) #1 /usr/share/fusiondirectory/plugins/addons/dashboard/class_dashBoardSystems.inc(61): dashboardSystems->argonaut_stats() #2 /usr/share/fusiondirectory/include/simpleplugin/class_simpleTabs.inc(92): dashboardSystems->__construct('', Object(dashboard), Object(tabs_dashboard), false) #3 /usr/share/fusiondirectory/plugins/addons/dashboard/tabs_dashBoard.inc(25): simpleTabs->__construct('dashboard', '', NULL) #4 /usr/share/fusiondirectory/include/class_objects.inc(280): tabs_dashboard->__construct('dashboard', '') #5 /usr/share/fusiondirectory/include/simpleplugin/class_simplePlugin.inc(2040): objects::open('', 'dashboard') #6 /usr/share/fusiondirectory/plugins/addons/dashboard/main. in /usr/share/fusiondirectory/include/class_objects.inc on line 90

Cheers.

Distribution Name and Version

Debian

FusionDirectory Version

php7

Origin of php packages

Debian stretch

Steps to Reproduce

1. install systems plugin (remove argonaut plugin)
2. go to dashboard
3. see the crash

Expected behavior:

No crash

Actual behavior:

It crash with an trace

Reproduces how often: 100%