Rename MergeException to IntegrationException

Gerrit master has a different name for the old MergeException since
change I344c70bf8.

Change-Id: I344c70bf8ffeb3a2823a65b5fcf09ea9bff82e72

github-plugin/src/main/java/com/googlesource/gerrit/plugins/github/git/PullRequestCreateChange.java

diff --git a/github-plugin/src/main/java/com/googlesource/gerrit/plugins/github/git/PullRequestCreateChange.java b/github-plugin/src/main/java/com/googlesource/gerrit/plugins/github/git/PullRequestCreateChange.java
index 00a659e..d72d450 100644
--- a/github-plugin/src/main/java/com/googlesource/gerrit/plugins/github/git/PullRequestCreateChange.java
+++ b/github-plugin/src/main/java/com/googlesource/gerrit/plugins/github/git/PullRequestCreateChange.java
@@ -32,7 +32,7 @@
 import com.google.gerrit.server.change.ChangeInserter;
 import com.google.gerrit.server.change.PatchSetInserter;
 import com.google.gerrit.server.git.BatchUpdate;
-import com.google.gerrit.server.git.MergeException;
+import com.google.gerrit.server.git.IntegrationException;
 import com.google.gerrit.server.git.UpdateException;
 import com.google.gerrit.server.git.validators.CommitValidators.Policy;
 import com.google.gerrit.server.project.InvalidChangeOperationException;
@@ -96,7 +96,7 @@
       final String pullRequestMessage, final String topic)
       throws NoSuchChangeException, EmailException, OrmException,
       MissingObjectException, IncorrectObjectTypeException, IOException,
-      InvalidChangeOperationException, MergeException, NoSuchProjectException,
+      InvalidChangeOperationException, IntegrationException, NoSuchProjectException,
       UpdateException, RestApiException {
     try (BatchUpdate bu =
         updateFactory.create(db, project.getNameKey(),