ROMFS: change shebang from #!zsh to #!/bin/sh

This was required for shellsheck.

ROMFS/px4fmu_common/init.d-posix/10016_iris

-#!nsh
+#!/bin/sh
 #
 # @name 3DR Iris Quadrotor SITL
 #

ROMFS/px4fmu_common/init.d-posix/1010_iris_opt_flow

-#!nsh
+#!/bin/sh
 #
 # @name 3DR Iris Quadrotor SITL (Optical Flow)
 #

ROMFS/px4fmu_common/init.d-posix/1011_iris_irlock

-#!nsh
+#!/bin/sh
 #
 # @name 3DR Iris Quadrotor SITL (irlock)
 #

ROMFS/px4fmu_common/init.d-posix/1012_iris_rplidar

-#!nsh
+#!/bin/sh
 #
 # @name 3DR Iris Quadrotor SITL (rplidar)
 #

ROMFS/px4fmu_common/init.d-posix/1013_iris_vision

-#!nsh
+#!/bin/sh
 #
 # @name 3DR Iris Quadrotor SITL (Vision)
 #

ROMFS/px4fmu_common/init.d-posix/1014_solo

-#!nsh
+#!/bin/sh
 #
 # @name Solo
 #

ROMFS/px4fmu_common/init.d-posix/1020_hippocampus

-#!nsh
+#!/bin/sh
 #
 # @name Hippocampus UUV
 #

ROMFS/px4fmu_common/init.d-posix/1030_plane

-#!nsh
+#!/bin/sh
 #
 # @name Plane SITL
 #

ROMFS/px4fmu_common/init.d-posix/1040_standard_vtol

-#!nsh
+#!/bin/sh
 #
 # @name Standard VTOL
 #

ROMFS/px4fmu_common/init.d-posix/1041_tailsitter

-#!nsh
+#!/bin/sh
 #
 # @name Quadrotor + Tailsitter
 #

ROMFS/px4fmu_common/init.d-posix/1042_tiltrotor

-#!nsh
+#!/bin/sh
 #
 # @name VTOL Tiltrotor
 #

ROMFS/px4fmu_common/init.d-posix/1060_rover

-#!nsh
+#!/bin/sh
 #
 # @name Rover
 #

ROMFS/px4fmu_common/init.d-posix/6011_typhoon_h480

-#!nsh
+#!/bin/sh
 #
 # @name Typhoon H480 SITL
 #

ROMFS/px4fmu_common/init.d/airframes/1000_rc_fw_easystar.hil

-#!nsh
+#!/bin/sh
 #
 # @name HILStar (XPlane)
 #

ROMFS/px4fmu_common/init.d/airframes/10015_tbs_discovery

-#!nsh
+#!/bin/sh
 #
 # @name Team Blacksheep Discovery
 #

ROMFS/px4fmu_common/init.d/airframes/10016_3dr_iris

-#!nsh
+#!/bin/sh
 #
 # @name 3DR Iris Quadrotor
 #

ROMFS/px4fmu_common/init.d/airframes/10017_steadidrone_qu4d

-#!nsh
+#!/bin/sh
 #
 # @name Steadidrone QU4D
 #

ROMFS/px4fmu_common/init.d/airframes/10018_tbs_endurance

-#!nsh
+#!/bin/sh
 #
 # @name Team Blacksheep Discovery Endurance
 #

ROMFS/px4fmu_common/init.d/airframes/1001_rc_quad_x.hil

-#!nsh
+#!/bin/sh
 #
 # @name HIL Quadcopter X
 #

ROMFS/px4fmu_common/init.d/airframes/1002_standard_vtol.hil

-#!nsh
+#!/bin/sh
 #
 # @name HIL Standard VTOL QuadPlane
 #