CodeOwnerSubmitRule: Fix exception logging

Rule errors are only returned in case an exception is caused by a user
misconfiguration (e.g. an invalid OWNERS file). In this case it is
sufficient to log a warning (without stacktrace).

For other exceptions CodeOwnerSubmitRule throws a
CodeOwnersInternalServerErrorException that will be logged on a higher
level. Hence CodeOwnerSubmitRule doesn't need to write an error log in
this case.

Signed-off-by: Edwin Kempin <ekempin@google.com>
Change-Id: I2000893ce343d56073c2e10096eb6be8dfc9cd61

java/com/google/gerrit/plugins/codeowners/backend/CodeOwnerSubmitRule.java

diff --git a/java/com/google/gerrit/plugins/codeowners/backend/CodeOwnerSubmitRule.java b/java/com/google/gerrit/plugins/codeowners/backend/CodeOwnerSubmitRule.java
index ea0f38a..b0ac537 100644
--- a/java/com/google/gerrit/plugins/codeowners/backend/CodeOwnerSubmitRule.java
+++ b/java/com/google/gerrit/plugins/codeowners/backend/CodeOwnerSubmitRule.java
@@ -145,10 +145,10 @@
         }
       }
       errorMessage += ".";
-      logger.atSevere().withCause(t).log(errorMessage);
       codeOwnerMetrics.countCodeOwnerSubmitRuleErrors.increment(cause);
 
       if (isRuleError) {
+        logger.atWarning().log(errorMessage);
         return Optional.of(ruleError(errorMessage));
       }
       throw new CodeOwnersInternalServerErrorException(errorMessage, t);