Increase the backport job to 2h
Increase the backport job to 2h

I previously incread the timeout of the general debian package build
job at: https://review.openstack.org/373389

but what was really needed was increasing the backport job timeout,
which is what this patch does. Indeed, some package are reaching the
timeout. For example, building python-pandas (needed by Gnocchi) can
take a little bit than 1h30. It already built once, then the other
times, it failed, as it took a bit longer.

Change-Id: I2b7f1dd5e10275ddda16282f361e6ed43a23d905

Tesora/tesora-project-config,Tesora/tesora-project-config,openstack-infra/project-config,openstack-infra/project-config