reset: Normalize exit codes
    
    Previously some usage error were treated as failures, and some failures
    caused the program to exit with strange exit codes (e.g. 255).  This
    patch normalizes the exit code to make sanlk-reset easier to consume by
    other programs.
    
    Exit codes:
    
      0  program succeeded
      1  program failed
      2  program used incorrectly
    
    Signed-off-by: Nir Soffer <nsoffer@redhat.com>