Use command -v instead of which

Unlike "which", which is a separate executable not always installed by
default, "command -v" is a shell built-in available at least for bash,
dash, and busybox shell.

Unlike "which", "command -v" is also easier to grep for, and it is
already used in a few places here.

Inspired by commit 57251d811.

Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>

contrib/dependencies/dnf-packages.sh

@@ -37,5 +37,4 @@ dnf install -y \
 	python3-setuptools \
 	python3-wheel \
 	rubygem-asciidoctor \
-	which \
 	xmlto

contrib/docker_cr.sh

@@ -418,7 +418,7 @@ resolve_path() {
 	local p
 
 	p="${2}"
-	if which realpath > /dev/null; then
+	if command -v realpath > /dev/null; then
 		p=$(realpath "${p}")
 	fi
 	${ECHO} "${1}: ${p}"
@@ -427,7 +427,7 @@ resolve_path() {
 resolve_cmd() {
 	local cpath
 
-	cpath=$(which "${2}")
+	cpath=$(command -v "${2}")
 	resolve_path "${1}" "${cpath}"
 }