cubicweb #1514 change the init runlevel of cubicweb [deprecated]

In CubicWeb 2.99.99, the launch of the application can be blocked by a non-running pyro. We have to check the init procedure and a possible conflict between dh_installinit and postinst.

priorityminor
typebug
done in3.5.11
load0.000
load left0.000
closed by<not specified>