style: fix inconsistent naming

We don't use "ID" anywhere else in the codebase.

src/renderer/controllers/torrent-list-controller.js

@@ -101,7 +101,7 @@ module.exports = class TorrentListController {
     function start () {
       ipcRenderer.send('wt-start-torrenting',
         s.torrentKey,
-        TorrentSummary.getTorrentID(s),
+        TorrentSummary.getTorrentId(s),
         s.path,
         s.fileModtimes,
         s.selections)

src/renderer/lib/torrent-summary.js

@@ -2,7 +2,7 @@ module.exports = {
   getPosterPath,
   getTorrentPath,
   getByKey,
-  getTorrentID,
+  getTorrentId,
   getFileOrFolder
 }
 
@@ -28,7 +28,7 @@ function getPosterPath (torrentSummary) {
 
 // Expects a torrentSummary
 // Returns a torrentID: filename, magnet URI, or infohash
-function getTorrentID (torrentSummary) {
+function getTorrentId (torrentSummary) {
   const s = torrentSummary
   if (s.torrentFileName) { // Load torrent file from disk
     return getTorrentPath(s)