Add 10s polling to allow transactions to complete

In some cases the check to ensure that all cars/people
were populated in the config store happened just before
the last few were there. This could be because of
any number of reasons (slow external environment,
testing in the middle of a GC operation maybe, etc)
Adding a polling period will account for this and
not give a false failure.

Change-Id: Ic9c7456da37b5c2cca694b2affc77e048a2f7b31
JIRA:INTTEST-54
Signed-off-by: Jamo Luhrsen <jluhrsen@redhat.com>