webadmin: RegisterVmInfoPanel - getAppList nullity check

RegisterVmInfoPanel -> updateTabsData -> vm.getAppList() might return
null on new VMs.

Change-Id: I78346b1df26b203e5075385c0c7e67e8bd4c3344
Bug-Url: https://bugzilla.redhat.com/1136756
Signed-off-by: Daniel Erez <derez@redhat.com>