scripts/env: Fix 56f813674a scripts/env: use command -v instead of which

We don't need to see how git will be executed and it produces non silent
output on 'scripts/env diff' commands when there are no differences
unlike before.

Re-introduce original silent behaviour.

Signed-off-by: Kevin Darbyshire-Bryant <ldir@darbyshire-bryant.me.uk>

scripts/env

@@ -57,7 +57,7 @@ env_init() {
 	if [ -z "$CREATE" ]; then
 		[ -d "$ENVDIR" ] || exit 0
 	fi
-	command -v git || error "Git is not installed"
+	command -v git >/dev/null || error "Git is not installed"
 	mkdir -p "$ENVDIR" || error "Failed to create the environment directory"
 	cd "$ENVDIR" || error "Failed to switch to the environment directory"
 	[ -d .git ] || {