ChangeCheckerImpl: Fix null guard check

The null guard check for the metaSha was wrong. This was actually
correct in the past and the mistake was introduced with
Ie45c2f1e209952ae7f2a91dc6b65c0c153f48376.

Change-Id: I302e54c238891ab8e1c37ecc77618e6d77c60381

src/main/java/com/ericsson/gerrit/plugins/highavailability/index/ChangeCheckerImpl.java

diff --git a/src/main/java/com/ericsson/gerrit/plugins/highavailability/index/ChangeCheckerImpl.java b/src/main/java/com/ericsson/gerrit/plugins/highavailability/index/ChangeCheckerImpl.java
index a392935..6fe0cd7 100644
--- a/src/main/java/com/ericsson/gerrit/plugins/highavailability/index/ChangeCheckerImpl.java
+++ b/src/main/java/com/ericsson/gerrit/plugins/highavailability/index/ChangeCheckerImpl.java
@@ -103,7 +103,7 @@
               || (computedChangeTs.get() == indexEvent.eventCreatedOn)
                   && (Objects.isNull(indexEvent.targetSha)
                       || repositoryHas(repo, indexEvent.targetSha))
-                  && (Objects.isNull(indexEvent.targetSha)
+                  && (Objects.isNull(indexEvent.metaSha)
                       || repositoryHas(repo, indexEvent.metaSha));
         }
       }