Message for empty list not visible after switching between include resolved and remove reslved

[KeenWarrior]

At https://github.com/hawkular/hawkular-android-client/blob/master/mobile/src/main/java/org/hawkular/client/android/fragment/AlertsFragment.java#L255

Apply similar as of #97 based on size of this.alerts

[shubhamvashisht]

Would like to work on in sir.