test: use sh shell in cli pretty test runner (POSIX)

Bash is apparently missing in the Alpine Docker.

Signed-off-by: Richard Alpe <richard@bit42.se>

test/case/cli_pretty/run.sh

@@ -1,9 +1,7 @@
-#!/bin/bash
+#!/bin/sh
 
 SCRIPT_PATH="$(dirname "$(readlink -f "$0")")"
 
-set -o pipefail
-
 if [ $# -lt 2 ]; then
     echo "Usage: $0 JSON-FILE MODULE [ ARGS ]"
     exit 1
@@ -14,6 +12,11 @@ module=$1; shift
 
 echo "1..1"
 
+if [ ! -e "$SCRIPT_PATH/$json" ]; then
+    echo "not ok 1 - $SCRIPT_PATH/$json not found"
+    exit 1
+fi
+
 cat "$SCRIPT_PATH/$json" | \
     "$SCRIPT_PATH"/../../../board/netconf/rootfs/lib/infix/cli-pretty \
     "$module" $*