Fix FloggerStringConcatenation bug pattern flagged by error prone

Change-Id: I681694dccc0679c850f9eb43337307eb49e59220
Details: https://errorprone.info/bugpattern/FloggerStringConcatenation
diff --git a/java/com/google/gerrit/httpd/auth/openid/OpenIdServiceImpl.java b/java/com/google/gerrit/httpd/auth/openid/OpenIdServiceImpl.java
index b685011..c655b6c 100644
--- a/java/com/google/gerrit/httpd/auth/openid/OpenIdServiceImpl.java
+++ b/java/com/google/gerrit/httpd/auth/openid/OpenIdServiceImpl.java
@@ -172,7 +172,7 @@
         aReq.addExtension(pape);
       }
     } catch (MessageException | ConsumerException e) {
-      logger.atSevere().withCause(e).log("Cannot create OpenID redirect for %s" + openidIdentifier);
+      logger.atSevere().withCause(e).log("Cannot create OpenID redirect for %s", openidIdentifier);
       return new DiscoveryResult(DiscoveryResult.Status.ERROR);
     }
 
diff --git a/java/com/google/gerrit/server/git/MultiProgressMonitor.java b/java/com/google/gerrit/server/git/MultiProgressMonitor.java
index 7e5c99f..15fbe3f 100644
--- a/java/com/google/gerrit/server/git/MultiProgressMonitor.java
+++ b/java/com/google/gerrit/server/git/MultiProgressMonitor.java
@@ -161,7 +161,7 @@
         volatileTotal.addAndGet(workUnits);
       } else {
         logger.atWarning().log(
-            "Total work has been finalized on sub-task " + getName() + " and cannot be updated");
+            "Total work has been finalized on sub-task %s and cannot be updated", getName());
       }
     }