Revert dgbuilder OS change

Reverted dgbuilder to ubuntu - start up script fails in alpine
due to missing packages.

Change-Id: I02a9d82d0c3dfc6b021951d2b1765cbdf720378d
Issue-ID: INT-1005
Signed-off-by: Timoney, Dan (dt5972) <dtimoney@att.com>
1 file changed