Reference AccountVisibility from correct package

Gerrit-core moved AccountVisibility to extensions in I0e88e05ca2. This
broke the reviewers plugin. This commit fixes it.

Change-Id: I8492e450e6bb78d94a1f47a39184695cd87ac3b7
diff --git a/src/main/java/com/googlesource/gerrit/plugins/reviewers/SuggestProjectReviewers.java b/src/main/java/com/googlesource/gerrit/plugins/reviewers/SuggestProjectReviewers.java
index 46d815a..4212e61 100644
--- a/src/main/java/com/googlesource/gerrit/plugins/reviewers/SuggestProjectReviewers.java
+++ b/src/main/java/com/googlesource/gerrit/plugins/reviewers/SuggestProjectReviewers.java
@@ -14,6 +14,7 @@
 
 package com.googlesource.gerrit.plugins.reviewers;
 
+import com.google.gerrit.extensions.common.AccountVisibility;
 import com.google.gerrit.extensions.common.SuggestedReviewerInfo;
 import com.google.gerrit.extensions.restapi.BadRequestException;
 import com.google.gerrit.extensions.restapi.RestReadView;
@@ -22,7 +23,6 @@
 import com.google.gerrit.server.IdentifiedUser;
 import com.google.gerrit.server.ReviewersUtil;
 import com.google.gerrit.server.ReviewersUtil.VisibilityControl;
-import com.google.gerrit.server.account.AccountVisibility;
 import com.google.gerrit.server.change.SuggestReviewers;
 import com.google.gerrit.server.config.GerritServerConfig;
 import com.google.gerrit.server.permissions.PermissionBackend;