main/mqtt-exec: fix typo in init.d script

(cherry picked from commit fb44c5eb1655dfe4bae3cb584e60fe74d7e6cb87)
Signed-off-by: Leonardo Arena <rnalrd@alpinelinux.org>
main/mqtt-exec: upgrade to 0.3

(cherry picked from commit f4dc2e0f386b5759f47cbfe93649c988683acda5)
Signed-off-by: Leonardo Arena <rnalrd@alpinelinux.org>
main/mqtt-exec: allow to specify more command options into init.d

(cherry picked from commit a64488c597a09e86bdecfe83dbb1e9089f46ef3c)
Signed-off-by: Leonardo Arena <rnalrd@alpinelinux.org>