Update SpringSecurityKerberosGrailsPlugin.groovy
Update SpringSecurityKerberosGrailsPlugin.groovy

change the package import corresponding to package naming changes in spring-security-core 2
http://grails-plugins.github.io/grails-spring-security-core/docs/manual/guide/newInV2.html
grails-plugins/grails-spring-security-kerberos