[pom] Update mockito to 2.2.15
[pom] Update mockito to 2.2.15

dblock/waffle,Waffle/waffle,hazendaz/waffle,Waffle/waffle,hazendaz/waffle,dblock/waffle,dblock/waffle,AriSuutariST/waffle,AriSuutariST/waffle,Waffle/waffle,dblock/waffle,hazendaz/waffle,AriSuutariST/waffle,AriSuutariST/waffle