Install sudo, create test user with ID 1000, install bash,
fix pidfile creation and pidfile chmod.

v2:
 * use sleep to give the criu daemon some time to start up

v3:
 * Andrei is of course right and sleep is not good solution.
   After adding --status-fd support to criu service, this
   is how we now detect that criu is ready.

v4:
 * This was much more complicated than expected which is related
   to the different versions of the tools on the different travis
   test targets. There seems to be a bug in bash on Ubuntu
    https://lists.gnu.org/archive/html/bug-bash/2017-07/msg00039.html
   which prevents using 'read -n1' on Ubuntu. As a workaround
   the result from CRIU's status FD is now read via python.

   Another problem was discovered on alpine with the loop restore test.
   CRIU says to use setsid even if the process is already using setsid.
   As a workaround, still with setsid, this process is now using
   shell-job true for checkpoint and restore.

Parts of v2 have been committed before. So the changes from this commit
are partially already in another commit.
Signed-off-by: Adrian Reber <areber@redhat.com>
Signed-off-by: Andrei Vagin <avagin@virtuozzo.com>