Increase token timeout to 15'

Avoid continuous token encryption / decryption
by allowing longer longevity up to 15'

Change-Id: Ib8bff7b30819aa9c4c8d0dfe19da9ce7e9e24b47
diff --git a/github-oauth/src/main/java/com/googlesource/gerrit/plugins/github/oauth/TokenCipher.java b/github-oauth/src/main/java/com/googlesource/gerrit/plugins/github/oauth/TokenCipher.java
index 9f4cbf6..7a71fa5 100644
--- a/github-oauth/src/main/java/com/googlesource/gerrit/plugins/github/oauth/TokenCipher.java
+++ b/github-oauth/src/main/java/com/googlesource/gerrit/plugins/github/oauth/TokenCipher.java
@@ -36,7 +36,7 @@
   private static final String ENC_ALGO = "AES";
   private static final Logger log = org.slf4j.LoggerFactory
       .getLogger(OAuthCookieProvider.class);
-  public static final Long COOKIE_TIMEOUT = 60 * 1000L;
+  public static final Long COOKIE_TIMEOUT = 15 * 60 * 1000L;
   
   private SecretKey aesKey;
   private byte[] IV;