Change log level from atInfo to atFine

Reduce how chatty this plugin is at default log levels.

Change-Id: Iec80def81b38892dbda11e83bbe040859fd8cee1

src/main/java/com/googlesource/gerrit/plugins/spannerrefdb/SpannerRefDatabase.java

diff --git a/src/main/java/com/googlesource/gerrit/plugins/spannerrefdb/SpannerRefDatabase.java b/src/main/java/com/googlesource/gerrit/plugins/spannerrefdb/SpannerRefDatabase.java
index 0593139..d291831 100644
--- a/src/main/java/com/googlesource/gerrit/plugins/spannerrefdb/SpannerRefDatabase.java
+++ b/src/main/java/com/googlesource/gerrit/plugins/spannerrefdb/SpannerRefDatabase.java
@@ -105,7 +105,7 @@
   private boolean doCompareAndPut(
       Project.NameKey project, String refName, String expectedValue, String newValue)
       throws GlobalRefDbSystemError {
-    logger.atInfo().log(
+    logger.atFine().log(
         "Do compare and put for %s / %s. Expected value: %s. New value: %s",
         project.get(), refName, expectedValue, newValue);
 
@@ -156,7 +156,7 @@
 
   @Override
   public boolean exists(Project.NameKey project, String refName) {
-    logger.atInfo().log("Checking if ref %s %s exists.", project.get(), refName);
+    logger.atFine().log("Checking if ref %s %s exists.", project.get(), refName);
     return get(project, refName) != null;
   }