install_prereq: Install aptitude non-interactively

Currently aptitude is installed using interactive mode. This patch
changes this to use the non-interactive mode as it can block
automatic dependencies installation, ex: CI, Docker build.

ASTERISK-28726 #close

Change-Id: I271ee00d230513a6f044810351a32d83b2181133

contrib/scripts/install_prereq

@@ -261,7 +261,7 @@ check_installed_zypper() {
 
 handle_debian() {
 	if ! [ -x "$(command -v aptitude)" ]; then
-		apt-get install aptitude
+		apt-get install -y aptitude
 	fi
 	extra_packs=`check_installed_debs $PACKAGES_DEBIAN`
 	$testcmd aptitude update