Move clamp release job to Ubuntu node

Some apt script tasks depend on Ubuntu and
we need to move to this node meanwhile we figure
how to make them work on Centos.
Disbable signing too since SIGUL only works on
Centos.

Change-Id: Ia4e0450ea0535ff5aacdfa37c81658ad2851117d
Issue-ID: CIMAN-250
Signed-off-by: Jessica Wagantall <jwagantall@linuxfoundation.org>
1 file changed