lib: fix lint issues

PR-URL: #473
Reviewed-By: Jack Horton <Jack.Horton@microsoft.com>
Reviewed-By: Seth Brenith <sethb@microsoft.com>

Author: kfarnung

lib/internal/process.js

@@ -182,7 +182,7 @@ function setupKillAndExit() {
   };
 }
 
-var ttdSigIntHandler = undefined;
+var ttdSigIntHandler;
 function setupSignalHandlers() {
   const signalWraps = Object.create(null);
   let Signal;

lib/trace_mgr.js

@@ -7,8 +7,8 @@ var reentrantDisable = true;
 var process = require('process');
 
 var lazyloadDone = false;
-var path = undefined;
-var fs = undefined;
+var path;
+var fs;
 
 ///////////////////////////////
 //Trace calls