Use new find(ReviewDb, String) method

Since I7231be3e ReviewDb instance must be passed into
AccountResolver methods.

Change-Id: I3222a3ba57b452c093214fe2c99e46b38e51edca
diff --git a/src/main/java/com/googlesource/gerrit/plugins/serviceuser/ServiceUserResolver.java b/src/main/java/com/googlesource/gerrit/plugins/serviceuser/ServiceUserResolver.java
index 5d88910..155cada 100644
--- a/src/main/java/com/googlesource/gerrit/plugins/serviceuser/ServiceUserResolver.java
+++ b/src/main/java/com/googlesource/gerrit/plugins/serviceuser/ServiceUserResolver.java
@@ -79,15 +79,17 @@
     committer.append(committerIdent.getEmailAddress());
     committer.append("> ");
 
-    Account account = resolver.find(committer.toString());
-    if (account == null) {
-      return null;
-    }
-    try {
-      return getServiceUser.get().apply(
-          new ServiceUserResource(genericUserFactory.create(account.getId())));
-    } catch (ResourceNotFoundException e) {
-      return null;
+    try (ReviewDb db = schema.open())  {
+      Account account = resolver.find(db, committer.toString());
+      if (account == null) {
+        return null;
+      }
+      try {
+        return getServiceUser.get().apply(
+            new ServiceUserResource(genericUserFactory.create(account.getId())));
+      } catch (ResourceNotFoundException e) {
+        return null;
+      }
     }
   }