TestNMWebServicesApps, TestRMWebServicesApps and TestRMWebServicesNodes fail on jdk7

It looks like the string changed from "const class" to "constant".

Tests run: 19, Failures: 3, Errors: 0, Skipped: 0, Time elapsed: 6.786 sec <<< FAILURE!
testNodeAppsStateInvalid(org.apache.hadoop.yarn.server.nodemanager.webapp.TestNMWebServicesApps) Time elapsed: 0.248 sec <<< FAILURE!
java.lang.AssertionError: exception message doesn't match, got: No enum constant org.apache.hadoop.yarn.server.nodemanager.containermanager.application.ApplicationState.FOO_STATE expected: No enum const class org.apache.hadoop.yarn.server.nodemanager.containermanager.application.ApplicationState.FOO_STATE