Don't use `kill -hup` in the launch script

The HUP signal was being used to stop the service and for some reason,
sometimes it was being ignored. This commit change forces the use of the
TERM signal (the default signal of kill).

Fixes gh-4378
Closes gh-4414

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

@@ -166,7 +166,7 @@ stop() {
 }
 
 do_stop() {
-  kill -HUP $1 &> /dev/null || { echoRed "Unable to kill process $1"; return 1; }
+  kill $1 &> /dev/null || { echoRed "Unable to kill process $1"; return 1; }
   for i in $(seq 1 60); do
     isRunning $1 || { echoGreen "Stopped [$1]"; rm -f $2; return 0; }
     sleep 1