Robustly add symlink and add for non-primary users

Amazingly, some apps still don't use the nativeLibraryPath. So add a lib
symlink for non-primary users to fix that.

Also, there was an error when the symlink existed that it would give up.
This shouldn't really happen, but in that case, just remove it and
create a new one to be safe.

Also, move the downgrade code to the appropriate place. This downgrade
case triggered the above symlink existing bug.

Bug: 7318366
Bug: 7371571
Change-Id: Ia175b36d98f00bdc2f2433b909aafd524eb34d15