Upgrade to logback 0.9.28

gradle/javaprojects.gradle

@@ -10,7 +10,7 @@ jstlVersion = '1.2'
 jettyVersion = '6.1.22'
 hsqlVersion = '1.8.0.10'
 slf4jVersion = '1.6.1'
-logbackVersion = '0.9.24'
+logbackVersion = '0.9.28'
 cglibVersion = '2.2'
 
 bundlorProperties = [