fix isInstalled check for the case when installSelfCheck is false

package.json

@@ -83,7 +83,7 @@
         "c9.ide.help.support": "#60e88f5680",
         "c9.ide.imgeditor": "#08bbc53578",
         "c9.ide.immediate": "#6845a93705",
-        "c9.ide.installer": "#75413dd79a",
+        "c9.ide.installer": "#d5310aa5c5",
         "c9.ide.mount": "#cb45b621f1",
         "c9.ide.navigate": "#64156c7f4a",
         "c9.ide.newresource": "#f1f0624768",