Special case init for android_is_in_vendor_process.

Init is executed without ld.config.<ver>.txt loaded (since sysprop
service isn't up in order for it to read ro.vndk.version and know <ver>). It uses the hard-coded
namespaces in the linker and therefore, does not know about the vndk namespace. That does not mean
it is not a system process.

Bug: 124128212

Test: Boot up device with selinux enforced, use camera to take pictures/ record videos (sanity)
Test: Watch movies on youtube (sanity)

Change-Id: If8701af2ee5dfa3bb36d0ce0a17a23808d184d9f
Signed-off-by: Jayant Chowdhary <jchowdhary@google.com>