Bump commons-io version to 2.4

The currently used version is from 2012. This dependency is not used in
gerrit core, but only in delete-project plugin.

Bug: Issue 13779
Change-Id: Ie15285654e473d35b7c118282cee71cb6b62d30b
diff --git a/WORKSPACE b/WORKSPACE
index 9981218..f88729e 100644
--- a/WORKSPACE
+++ b/WORKSPACE
@@ -921,8 +921,8 @@
 
 maven_jar(
     name = "commons-io",
-    artifact = "commons-io:commons-io:2.2",
-    sha1 = "83b5b8a7ba1c08f9e8c8ff2373724e33d3c1e22a",
+    artifact = "commons-io:commons-io:2.4",
+    sha1 = "b1b6ea3b7e4aa4f492509a4952029cd8e48019ad",
 )
 
 maven_jar(