Remove bats installation script and make target

While convenient, it can be problematic to rely on a Makefile to install
software.  This was found to be the case across multiple environments
WRT `bats`.  Fix this by removing the install script and target.  A
future commit will ensure the correct version of `bats` is present in
all CI environments where it's required.

Signed-off-by: Chris Evich <cevich@redhat.com>

hack/install_bats.sh

@@ -1,22 +0,0 @@
-#!/usr/bin/env bash
-
-set -e
-
-die() { echo "${1:-No error message given} (from $(basename $0))"; exit 1; }
-
-if [[ "$(type -t bats)" != "" ]]; then
-	# bats is already installed.
-	exit 0
-fi
-
-buildDir=$(mktemp -d)
-git clone https://github.com/bats-core/bats-core $buildDir
-
-pushd $buildDir
-pwd
-git reset --hard ${VERSION}
-echo "Installing bats to /usr/local (requires root)"
-sudo ./install.sh /usr/local
-popd
-
-rm -rf $buildDir