upstart: add blocknet which blocks net until after cloud-init-local

This makes it so networking wont start to come up until after
cloud-init-local has had a chance to search local datasources
and set /etc/network/interfaces.

The changes most likely need to still be done for systemd.
allow local disabling of blocknet
netinfo: log error on failure of route info
upstart/cloud-init-nonet.conf: do not exit on existance of obj.pkl

not sure why this was here.
the intent must of have been to allow for a local datasource
to continue booting and not annoyingly block waiting for network information
(if ithere was no network information).

However, that seems wrong.

If the datasource wipes /etc/network/interfaces and there are no network
interfaces then we're probably breaking that use case here.  However we're
fixing the other more common case.
upstart: add blocknet which blocks net until after cloud-init-local

This makes it so networking wont start to come up until after
cloud-init-local has had a chance to search local datasources
and write /etc/network/interfaces.

The changes most likely need to still be done for systemd.
upstart/cloud-init-nonet.conf: only mention wait if larger than 5 seconds

silently wait 5 seconds for networking to come up.
We started seeing the message more now, as we are now blocking
the networking from coming up until cloud-init-local is done.

Previously that would have happened in parallel, and we were less likely
to see that message.