Core: Fix qbs build.

Change-Id: I8dfc2aa436537b3bd5da0a090397cc8a473b36a7
Reviewed-by: hjk <hjk121@nokiamail.com>

src/plugins/coreplugin/coreplugin.qbs

@@ -98,6 +98,9 @@ QtcPlugin {
             "styleanimator.cpp", "styleanimator.h",
             "tabpositionindicator.cpp", "tabpositionindicator.h",
             "textdocument.cpp", "textdocument.h",
+            "themesettings.cpp",
+            "themesettings.h",
+            "themesettings.ui",
             "toolsettings.cpp", "toolsettings.h",
             "variablechooser.cpp", "variablechooser.h",
             "vcsmanager.cpp", "vcsmanager.h",