bootstrap-update: Removed integrity-checker.sh call to avoid infinite loop

Removed to avoid a loop error caused by a bug either in integrity-checker.sh
or in this script, and because there is already a MD5 verification of the
package.

The bug ocurred while running integrity-checker.sh after an update, when the
inep or the proxy files were corrupted, causing the script to keep
downloading and installing the update package.

Signed-off-by: Erik Alexandre Pucci <eap08@c3sl.ufpr.br>
Acked-by: Adriano da Luz <al08@c3sl.ufpr.br>
Acked-by: Josiney de Souza <josineys@c3sl.ufpr.br>