Catch only relevant signals.
Catch only relevant signals.

Unintended consequence: previously, we were catching all signals.

This means that we were catching SIGINT when trying to Ctrl-C
from the command line, which could be quite frustrating.

Change-Id: Iaee52e699e6cbbac9c4010b8da3941f199f00916

viraptor/novm,viraptor/novm,viraptor/novm,google/novm,viraptor/novm,google/novm,nathanaelle/novm,nathanaelle/novm,google/novm,google/novm,nathanaelle/novm,nathanaelle/novm