fix typo in help text

git-svn-id: https://simplesamlphp.googlecode.com/svn/trunk@1388 44740490-163a-0410-bde0-09ae8108e29a

modules/statistics/bin/loganalyzer.php

@@ -83,7 +83,7 @@ This program parses and aggregates SimpleSAMLphp log files.
 
 Options:
 	-d, --debug			Used when configuring the log file syntax. See doc.
-	-dry-run			Aggregate but do not store the results.
+	--dry-run			Aggregate but do not store the results.
 
 ');
 }