Makefile: Use 'command -v selinuxenabled' instead of hard-coded path
The hard-coded path landed in (Make sure selinuxenabled
exists before executing it, 2016-10-17, but there's no need to
require that path.  Using 'command -v' (in POSIX [1]) supports anyone
who has selinuxenabled in their PATH.
[1]:
@@ -17,7 +17,7 @@ CRICTL_CONFIG_DIR=${DESTDIR}/etc
BASHINSTALLDIR=${PREFIX}/share/bash-completion/completions
OCIUMOUNTINSTALLDIR=$(PREFIX)/share/oci-umount/oci-umount.d
-SELINUXOPT ?= $(shell test -x /usr/sbin/selinuxenabled && selinuxenabled && echo -Z)
+SELINUXOPT ?= $(shell command -v selinuxenabled && selinuxenabled && echo -Z)
PACKAGES ?= $(shell go list -tags "${BUILDTAGS}" ./... | grep -v github.com/kubernetes-incubator/cri-o/vendor)
COMMIT_NO := $(shell git rev-parse HEAD 2> /dev/null || true)
