Update checkstyle.go to refer to checkstyle 5.7.

Change-Id: I15a68ad9bb37b05c080f96e66f697c9a3a29a4d0
diff --git a/checkstyle/checkstyle.go b/checkstyle/checkstyle.go
index fe3ac31..e81121f 100644
--- a/checkstyle/checkstyle.go
+++ b/checkstyle/checkstyle.go
@@ -27,7 +27,7 @@
 	"os/exec"
 )
 
-var checkstylejar = flag.String("checkstylejar", "../tools/antlib/checkstyle-all-4.2.jar", "path to checkstyle jar")
+var checkstylejar = flag.String("checkstylejar", "../tools/antlib/checkstyle-5.7-all.jar", "path to checkstyle jar")
 
 // Error represents a specific instance of an error reported by checkstyle.
 type Error struct {
diff --git a/cmd/presubmitter/presubmitter.go b/cmd/presubmitter/presubmitter.go
index bcc47dc..95131fb 100644
--- a/cmd/presubmitter/presubmitter.go
+++ b/cmd/presubmitter/presubmitter.go
@@ -35,7 +35,7 @@
 uploaded changes.
 
 Lastly, presubmitter expects to find the checkstyle JAR at
-../tools/antlib/checkstyle-all-4.2.jar, but this can also be changed using
+../tools/antlib/checkstyle-5.7-all.jar, but this can also be changed using
 the -checkstylejar flag.
 */
 package main