fix permissions errors for tmp-mksh as well as check for bugged chroot

This was the only way I could get linxudeploy working on android 4.4.2 (kernel 3.4.0):

This is mentioned here: http://forum.xda-developers.com/galaxy-s3/themes-apps/app-linux-deploy-t1929013/page3 and #60.

@meefik, I think you said this was fixed in 1.4.6, but I still run into the same issue mentioned in #60.

The relevant fix mentioned above:

``` bash
su -
cd /data/data/ru.meefik.linuxdeploy/linux/bin
rm sh chroot
ln -s /system/bin/mksh sh
ln -s /system/xbin/busybox chroot
```

However, after doing this, linxudeploy still didn't work for me due to a bugged /system busybox binary wherein busybox thought chroot was chattr. The new code also accounts for this and tells the user to upgrade to the latest busybox, or use the Busybox X installer (which worked for me).

I've modified the linuxdeploy script to account for this also.

This is untested, but I believe it should work. I'm relatively new to android, so I'm open to having any gotchas pointed out to me.

@meefik, I hope this gets fixed. Thank you for a great app.