remove explicit mockito-all dependency from slf4j-mockito example
remove explicit mockito-all dependency from slf4j-mockito example

* it's a transitive dependency of powermock-api-mockito

thekingnothing/powermock,gauee/powermock,thekingnothing/powermock,Monits/powermock,jayway/powermock,powermock/powermock,gauee/powermock,jayway/powermock,Monits/powermock,gstamac/powermock,darxriggs/powermock,jayway/powermock,gstamac/powermock,hazendaz/powermock,thekingnothing/powermock