misc: ignore jshint files

They are automatically created by precommit-hook:
362a202498/bin/install (L5-L6)

.gitignore

@@ -71,3 +71,8 @@ buck-out/
 
 # Bundle artifact
 *.jsbundle
+
+# precommit-hook
+.jshintignore
+.jshintrc
+