Fix tacker installation

Sometimes commands are exeucuted before last one was finished, for
example here:
https://build.opnfv.org/ci/job/fuel-deploy-virtual-daily-colorado/117/console
Try set custom prompt to eliminate false matching and add additional sleep
after git package installation.

Change-Id: I0fd1b5410c7870ff2a074e050069efc3b61b0d79
Signed-off-by: Michal Skalski <mskalski@mirantis.com>