rename /bin/bash to /bin/sh to scripts in 'scripts folder (#302)

* Update genGitHdr.sh

* Update linux_makeIcons.sh

* Update unix_debug_build.sh

scripts/genGitHdr.sh

@@ -1,4 +1,4 @@
-#!/bin/bash
+#!/bin/sh
 
 OUTPUT_DIR=$1;
 

scripts/linux_makeIcons.sh

@@ -1,4 +1,4 @@
-#!/bin/bash
+#!/bin/sh
 
 SRC_PNG=../fceux1.png
 ICON_PATH=/usr/share/icons/hicolor

scripts/unix_debug_build.sh

@@ -1,4 +1,4 @@
-#!/bin/bash
+#!/bin/sh
 
 CLEAN_BUILD=0;
 MAKE_ARGS="";