bootstrap-install: Added "-q" (quiet) option in sudoers(1) grep(1)

Signed-off-by: Erik Alexandre Pucci <eap08@c3sl.ufpr.br>
Acked-by: Danilo Kiyoshi Simizu Yorinori <danilok@c3sl.ufpr.br>
Acked-by: Victor Tarabola Cortiano <vtc10@c3sl.ufpr.br>

bootstraps/bootstrap-install

@@ -88,7 +88,7 @@ if ! test -n "${PROJECTOR}" -o -f "/usr/sbin/projetor" -o \
           -f "/etc/cmpc-release" -o -n "${UCA_SERVER}" -o \
           -n "${UCA_CLASSMATE}"; then
     # Add root permissions to seed_mec user, without the need of password
-    if ! grep "seed_mec" /etc/sudoers; then
+    if ! grep -q "seed_mec" /etc/sudoers; then
         if ! $(echo "seed_mec ALL=NOPASSWD: ALL" >> /etc/sudoers); then
             printf "ERRO: Falha ao adicionar permissões de super-usuário %b" \
                    "ao seed_mec.\n"