rabbitmq-script-wrapper: Use "exec" to execute the subsequent script

Without this, a new process is spawned to execute the script. This new
process won't receive the signals delivered to the process initially
started.

A user reported this problem with RabbitMQ in Docker: when the service
must be stopped, the SIGTERM doesn't make it to the server which
continues to run.

Author: dumbbell

packaging/common/rabbitmq-script-wrapper

@@ -30,14 +30,14 @@ cd /var/lib/rabbitmq
 SCRIPT=`basename $0`
 
 if [ `id -u` = `id -u rabbitmq` -a "$SCRIPT" = "rabbitmq-server" ] ; then
-    /usr/lib/rabbitmq/bin/rabbitmq-server "$@" @STDOUT_STDERR_REDIRECTION@
+    exec /usr/lib/rabbitmq/bin/rabbitmq-server "$@" @STDOUT_STDERR_REDIRECTION@
 elif [ `id -u` = `id -u rabbitmq` -o "$SCRIPT" = "rabbitmq-plugins" ] ; then
     if [ -f $PWD/.erlang.cookie ] ; then
         export HOME=.
     fi
-    /usr/lib/rabbitmq/bin/${SCRIPT} "$@"
+    exec /usr/lib/rabbitmq/bin/${SCRIPT} "$@"
 elif [ `id -u` = 0 ] ; then
-    @SU_RABBITMQ_SH_C@ "/usr/lib/rabbitmq/bin/${SCRIPT} ${CMDLINE}"
+    exec @SU_RABBITMQ_SH_C@ "/usr/lib/rabbitmq/bin/${SCRIPT} ${CMDLINE}"
 else
     /usr/lib/rabbitmq/bin/${SCRIPT}
     echo