Fix merge-audio script

Signed-off-by: Bensuperpc <bensuperpc@gmail.com>

Makefile

@@ -20,7 +20,7 @@
 #//////////////////////////////////////////////////////////////
 PROJECT_NAME := scripts
 SHELL := bash
-VERSION := 1.3.16
+VERSION := 1.3.17
 RM := rm
 
 all: install

audio/merge-audio.sh

@@ -27,7 +27,7 @@ elif (($# == 4)); then
     ffmpeg -i "$1" -i "$2" -i "$3" \
         -filter_complex '[0:0][1:0][2:0]concat=n=3:v=0:a=1[out]' \
         -map '[out]' "$4"
-elif (($# == 6)); then
+elif (($# == 5)); then
     ffmpeg -i "$1" -i "$2" -i "$3" -i "$4" \
         -filter_complex '[0:0][1:0][2:0][3:0]concat=n=4:v=0:a=1[out]' \
         -map '[out]' "$5"