improves upid_read_status with:
* ignore multiple newlines at the end
* remove all code that could panic (array index access)
the one place where we access with '[pos+1..]' is ok since
we explicitely test the len of the vector, this is done to
let rust optimize away the range checks, so it cannot panic
Signed-off-by: Dominik Csapak <d.csapak@proxmox.com>