QtcPlugin.qbs: make every plugin depend on ExtensionSystem

Remove ExtensionSystem from the core plugin's ProductModule.
Every plugin must depend on ExtensionSystem, not only the ones that depend
on Core.

Change-Id: I9f72653c5ef61bfab2b478f61e5723140c0896ec
Reviewed-by: Christian Kandeler <christian.kandeler@digia.com>

src/plugins/QtcPlugin.qbs

@@ -19,6 +19,7 @@ Product {
         return name;
     }
 
+    Depends { name: "ExtensionSystem" }
     Depends { name: "pluginspec" }
     Depends { name: "cpp" }
     Depends {

src/plugins/coreplugin/coreplugin.qbs

@@ -11,7 +11,6 @@ QtcPlugin {
         ]
     }
     Depends { name: "Utils" }
-    Depends { name: "ExtensionSystem" }
     Depends { name: "Aggregation" }
     Depends { name: "app_version_header" }
 
@@ -251,7 +250,6 @@ QtcPlugin {
     ProductModule {
         Depends { name: "cpp" }
         Depends { name: "Aggregation" }
-        Depends { name: "ExtensionSystem" }
         Depends { name: "Utils" }
     }
 }

src/plugins/qbsprojectmanager/qbsprojectmanager.qbs

@@ -14,7 +14,6 @@ QtcPlugin {
     Depends { name: "ProjectExplorer" }
     Depends { name: "Core" }
     Depends { name: "CppTools" }
-    Depends { name: "ExtensionSystem" }
     Depends { name: "TextEditor" }
     Depends { name: "QtSupport" }
     Depends { name: "QmlJS" }

src/plugins/updateinfo/updateinfo.qbs

@@ -7,7 +7,6 @@ QtcPlugin {
 
     Depends { name: "cpp" }
     Depends { name: "Core" }
-    Depends { name: "ExtensionSystem" }
     Depends { name: "Qt"; submodules: ["widgets", "xml", "network"] }
 
     property bool enable: false