utils: remove obsolete vagrant scripts

Vagrantfile has long been removed in !5288. This commit further
removes the obsolete vagrant scripts in the tree.

utils/vagrant/bootstrap-deb.sh

-#!/bin/sh
-apt-get update
-apt-get build-dep -y ghc

utils/vagrant/bootstrap-rhel.sh

-#!/bin/sh
-yum update -y
-yum install -y glibc-devel ncurses-devel gmp-devel autoconf automake libtool \
- gcc make python ghc git