Install procps if not installed.

This is required to have sysctl, which is used by `slapos node format`
when setting up the network.

See merge request nexedi/slapos.core!655

master/bt5/slapos_web_deploy/PathTemplateItem/web_page_module/deploy_base_setup.txt

@@ -57,6 +57,7 @@ fi
 is_package_installed unzip || install_package unzip
 is_package_installed openssl || install_package openssl
 is_package_installed iproute2 || install_package iproute2
+is_package_installed procps || install_package procps
 
 if ! is_suse && ! is_ubuntu || [[ $DISTRO = wheezy || $DISTRO == jessie || $DISTRO == stretch || $DISTRO == xenial || $DISTRO == bionic ]]; then
   is_package_installed python-pip || install_package python-pip