Added support to update the agent even when inep or proxy files are missing

The new necessity of install the system with an empty inep/proxy had to be
implemented in the update bootstrap. This patch allows the update process to
run properly on a missing inep/proxy system.

Acked-by: Danilo K. S. Yorinori <danilok@c3sl.ufpr.br>
Signed-off-by: Vinicius Ruoso <vkr07@c3sl.ufpr.br>