Fix an issue with System Designer extensions

Author: ecarriou

src/systems/classes/_Channel-class.json

@@ -97,7 +97,7 @@
       "_id": "1e9021bd4e1bc6e",
       "component": "_Channel",
       "state": "$systemInstalled",
-      "action": "function $systemInstalled(id) {\n  var systems = null,\n    dependencies = [],\n    master = [],\n    canStart = true;\n\n  if (id !== 'e89c617b6b15d24') {\n    // if all systems are installed\n    systems = $db._System.find({});\n\n    systems.forEach(function (system) {\n      var sys = this.require(system._id);\n      if (sys.state() === 'none') {\n        canStart = false;\n      }\n    }.bind(this));\n\n    // start all the systems\n    if (canStart) {\n      dependencies = $db._System.find({\n        'master': false\n      });\n\n      dependencies.forEach(function (dep) {\n        var system = this.require(dep._id);\n        channel = this.require('channel');\n\n        if (system.state() === 'resolved') {\n          system.state('starting');\n          system.start();\n          channel.$systemStarted(dep._id);\n          system.state('active');\n        }\n      }.bind(this));\n\n      master = $db._System.find({\n        'master': true\n      });\n\n      master.forEach(function (dep) {\n        var system = this.require(dep._id);\n        channel = this.require('channel');\n\n        if (system.state() === 'resolved') {\n          system.state('starting');\n          system.start();\n          channel.$systemStarted(dep._id);\n          system.state('active');\n        }\n      }.bind(this));\n    }\n  }\n}",
+      "action": "function $systemInstalled(id) {\n  var systems = null,\n    dependencies = [],\n    master = [],\n    canStart = true;\n\n  if (id !== 'e89c617b6b15d24') {\n    // if all systems are installed\n    systems = $db._System.find({});\n\n    systems.forEach(function (system) {\n      var sys = this.require(system._id);\n      if (sys && sys.state && sys.state() === 'none') {\n        canStart = false;\n      }\n    }.bind(this));\n\n    // start all the systems\n    if (canStart) {\n      dependencies = $db._System.find({\n        'master': false\n      });\n\n      dependencies.forEach(function (dep) {\n        var system = this.require(dep._id);\n        channel = this.require('channel');\n\n        if (system.state() === 'resolved') {\n          system.state('starting');\n          system.start();\n          channel.$systemStarted(dep._id);\n          system.state('active');\n        }\n      }.bind(this));\n\n      master = $db._System.find({\n        'master': true\n      });\n\n      master.forEach(function (dep) {\n        var system = this.require(dep._id);\n        channel = this.require('channel');\n\n        if (system && system.state && system.state() === 'resolved') {\n          system.state('starting');\n          system.start();\n          channel.$systemStarted(dep._id);\n          system.state('active');\n        }\n      }.bind(this));\n    }\n  }\n}",
       "useCoreAPI": true,
       "core": true
     }