Set the working directory to that of the jar when using start-stop-daemon

By default, start-stop-daemon will chdir to the root directory before
starting the process. This prevents an application.properties file that
sits alongside the jar from being found.

This commit updates the call to start-stop-daemon to use --chdir to
set the working directory to that of the jar that’s being launched.

Closes gh-4281

spring-boot-tools/spring-boot-loader-tools/src/main/resources/org/springframework/boot/loader/tools/launch.script

@@ -122,7 +122,8 @@ start() {
 }
 
 do_start() {
-  pushd $(dirname "$jarfile") > /dev/null
+  working_dir=$(dirname "$jarfile")
+  pushd "$working_dir" > /dev/null
   if [[ -n "$run_user" ]]; then
     mkdir "$PID_FOLDER" &> /dev/null
     checkPermissions || return $?
@@ -136,6 +137,7 @@ do_start() {
         --make-pidfile --pidfile $pid_file \
         --background --no-close \
         --startas $javaexe \
+        --chdir "$working_dir"
         -- \
         -Dsun.misc.URLClassPath.disableJarChecking=true $JAVA_OPTS \
         -jar $jarfile $RUN_ARGS "$@" \