clean up android.ini

Author: zilongshanren

build/android.ini

@@ -11,7 +11,7 @@ cfg_android_ndk_path=/Users/guanghui/AndroidDev/android-ndk-r10c
 
 #help message strings goes here
 cfg_help_arch_string="arm,armv7,x86,arm64"
-cfg_help_sample_string="./build.sh -p=android --libs=png --arch=arm,armv7,arm64 [--api=21 --gcc=4.9] --mode=debug"
+cfg_help_sample_string="./build.sh -p=android --libs=png --arch=arm,armv7,arm64 --mode=debug"
 
 cfg_build_machine="x86_64-apple-darwin14"
 cfg_x86_host_machine="i686-linux-android"