Bazel: Fix MisusedWeekYear error detected by ErrorProne

Building Gerrit code with Bazel revealed MisusedWeekYear error detected
by ErrorProne: [1].

[1] http://errorprone.info/bugpattern/MisusedWeekYear
Change-Id: I95edf77a1922840e9e37a6125ba7d094be297516
diff --git a/gerrit-gpg/src/test/java/com/google/gerrit/gpg/PublicKeyCheckerTest.java b/gerrit-gpg/src/test/java/com/google/gerrit/gpg/PublicKeyCheckerTest.java
index c11aa31..bd71bc5 100644
--- a/gerrit-gpg/src/test/java/com/google/gerrit/gpg/PublicKeyCheckerTest.java
+++ b/gerrit-gpg/src/test/java/com/google/gerrit/gpg/PublicKeyCheckerTest.java
@@ -229,7 +229,7 @@
         "Key is revoked (key material has been compromised): test6 compromised";
     assertProblems(k, problem);
 
-    SimpleDateFormat df = new SimpleDateFormat("YYYY-MM-dd HH:mm:ss");
+    SimpleDateFormat df = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
     PublicKeyChecker checker = new PublicKeyChecker()
         .setStore(store)
         .setEffectiveTime(df.parse("2010-01-01 12:00:00"));
@@ -392,7 +392,7 @@
   }
 
   private static Date parseDate(String str) throws Exception {
-    return new SimpleDateFormat("YYYY-MM-dd HH:mm:ss Z").parse(str);
+    return new SimpleDateFormat("yyyy-MM-dd HH:mm:ss Z").parse(str);
   }
 
   private static List<String> list(String first, String[] rest) {
diff --git a/gerrit-gpg/src/test/java/com/google/gerrit/gpg/PushCertificateCheckerTest.java b/gerrit-gpg/src/test/java/com/google/gerrit/gpg/PushCertificateCheckerTest.java
index ee07d55..12a911e 100644
--- a/gerrit-gpg/src/test/java/com/google/gerrit/gpg/PushCertificateCheckerTest.java
+++ b/gerrit-gpg/src/test/java/com/google/gerrit/gpg/PushCertificateCheckerTest.java
@@ -139,7 +139,7 @@
   @Test
   public void signatureByExpiredKeyBeforeExpiration() throws Exception {
     TestKey key3 = expiredKey();
-    Date now = new SimpleDateFormat("YYYY-MM-dd HH:mm:ss Z")
+    Date now = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss Z")
         .parse("2005-07-10 12:00:00 -0400");
     PushCertificate cert = newSignedCert(validNonce(), key3, now);
     assertNoProblems(cert);