Fix loop0p2 does not exist on F19

On Fedora 19, there is a delay between the time loop0p2
is created to the time it is ready to be mounted.

This patches waits for 5 seconds for /dev/mapper/loop0p2
to be accessible. If it is not ready then the script
exits with status 1.

Fixes: bug #1197340

Change-Id: Iff0cfd0566673799a77500e0e24954f5f3743a17