Log: cib: Drop the message serverity now that the cause is well understood

t0: node1 starts
t1: node3 "everyone make change ABC"
t2: everyone receives the ABC message
t3: node1 to node2 "please send me your cib, i'm out of date"
t4: node4 "everyone make change DEF"
t5: node2 to node1 "here you go"
t6: everyone receives the DEF message
t7: everyone receives the t6 message
t8: node1 - dude, this is out of date "current num_updates is greater
than the replacement"

Or in english, it happens when new commands arrive between the sync
request being sent and the response being sent out.