Change a silent removal to an error
Change a silent removal to an error

syscalls.txt should already not contain __user, so this change
is for better process

PiperOrigin-RevId: 284321870
Change-Id: Id34ebb8c149e8546cda61601543f0a0377dad3bb

google/asylo,google/asylo,google/asylo,google/asylo,google/asylo,google/asylo