cert-checker: Remove unused field ReportDirectoryPath (#6704)

cmd/cert-checker/main.go

@@ -409,11 +409,10 @@ type Config struct {
 		DB cmd.DBConfig
 		cmd.HostnamePolicyConfig
 
-		Workers             int
-		ReportDirectoryPath string
-		UnexpiredOnly       bool
-		BadResultsOnly      bool
-		CheckPeriod         cmd.ConfigDuration
+		Workers        int
+		UnexpiredOnly  bool
+		BadResultsOnly bool
+		CheckPeriod    cmd.ConfigDuration
 
 		// AcceptableValidityDurations is a list of durations which are
 		// acceptable for certificates we issue.