usgs: add FIXME comment re `data`

The logic for passing data around seems to be broken to me.

apps/lint_exemptions.js

@@ -528,7 +528,7 @@ module.exports = {
     ]
   },
   "apps/usgs/settings.js": {
-    "hash": "af1b7bc7e041c1e6988b407b6c8ee66dbd6a0e181a20caf102d2abdb6dbd5ac0",
+    "hash": "00ee672a6920f5667bfbd2988fd2853cfd579895a843ae036a00028dcb13878d",
     "rules": [
       "no-undef"
     ]

apps/usgs/settings.js

@@ -19,6 +19,9 @@
   }
 
 function popSubMenu() {
+  // FIXME: Linter complains that `data` is not defined. When I defined it 
+  // instead complained that it's not used (no-unused-vars).
+  // Also looking at `getDataStreams` it doesn't return anything so this seems wrong.
   data = getDataStreams();
 }
 function popSubMenuData(data) {