repair sharing example

repair sharing example

the note re: "we dont have to guess" is wrong.
engine_from_config() returns an engine.   It seems
like this example was edited a few times and
was not completely checked (it was me, for sure).

for now just use two separate blocks to eliminate
any problems

Change-Id: Ib44671526d0f570ed88dd3b1c77d078c1afbf3eb