Handle deleted files

Author: piotr-oles

lib/IncrementalChecker.js

@@ -150,7 +150,14 @@ IncrementalChecker.prototype.getLints = function (cancellationToken) {
   workSet.forEach(function (fileName) {
     cancellationToken.throwIfCancellationRequested();
 
-    this.linter.lint(fileName, undefined, this.linterConfig);
+    try {
+      this.linter.lint(fileName, undefined, this.linterConfig);
+    } catch (e) {
+      if (fs.existsSync(fileName)) {
+        // it's not because file doesn't exist - throw error
+        throw e;
+      }
+    }
   }.bind(this));
 
   // set lints in files register