Allow debuggerd to redirect requests.

On 64 bit systems, all requests will first go to the 64 bit debuggerd
which will redirect to the 32 bit debuggerd if necessary. This avoids
any permissions problems where a java process needs to be able to
read the elf data for executables. Instead the permissions are granted
to debuggerd instead.

Also remove the permissions to read the /system/bin executables from
dumpstate since they aren't necessary any more.

Bug: https://code.google.com/p/android/issues/detail?id=97024
Change-Id: I80ab1a177a110aa7381c2a4b516cfe71ef2a4808