Revert "stack protector: use AT_RANDOM"

Revert "stack protector: use AT_RANDOM"

The AT_RANDOM changes broke setuid / setgid executables
such as "ping". When the linker executes a setuid program,
it cleans the environment, removing any invalid environment
entries, and adding "NULL"s to the end of the environment
array for each removed variable. Later on, we try to determine
the location of the aux environment variable, and get tripped
up by these extra NULLs.

Reverting this patch will get setuid executables working again,
but getauxval() is still broken for setuid programs because of
this bug.

This reverts commit e3a49a8661125f24aec8a1453e54b3b78005e21e.

Change-Id: I05c58a896b1fe32cfb5d95d43b096045cda0aa4a