Fix NPE if in GetPreference if globally no link decoration is set

Change-Id: I3ea8611b666036a59e8b86325f2d22b15b098561
Signed-off-by: Edwin Kempin <edwin.kempin@sap.com>
diff --git a/src/main/java/com/googlesource/gerrit/plugins/imagare/GetPreference.java b/src/main/java/com/googlesource/gerrit/plugins/imagare/GetPreference.java
index b2f506e..82dfcd8 100644
--- a/src/main/java/com/googlesource/gerrit/plugins/imagare/GetPreference.java
+++ b/src/main/java/com/googlesource/gerrit/plugins/imagare/GetPreference.java
@@ -71,7 +71,7 @@
 
     info.linkDecoration =
         db.getEnum(PREFERENCE, username, KEY_LINK_DECORATION,
-            globalCfg.linkDecoration);
+            Objects.firstNonNull(globalCfg.linkDecoration, LinkDecoration.NONE));
     if (LinkDecoration.NONE.equals(info.linkDecoration)) {
       info.linkDecoration = null;
     }