AP_Scripting: Misc. small improvements.

Typo fix
Removed unused variable

libraries/AP_Scripting/applets/VTOL-quicktune.lua

@@ -401,7 +401,7 @@ function adjust_gain(pname, value)
       local FF = params[ffname]
       if FF:get() > 0 then
          -- if we have any FF on an axis then we don't couple I to P,
-         -- usually we want I = FF for a one sectond time constant for trim
+         -- usually we want I = FF for a one second time constant for trim
          return
       end
       param_changed[iname] = true

libraries/AP_Scripting/applets/forward_flight_motor_shutdown.lua

@@ -93,7 +93,6 @@ local slew
 local slew_pwm
 function update()
 
-  local switch_pos = switch:get_aux_switch_pos()
   if switch:get_aux_switch_pos() == 2 then
     if not script_enabled then
       gcs:send_text(0, "Lua: Forward flight motor shutdown enabled")