setroubleshoot: Fix sealert message for capability2
    
    Sealert didn't know "capability2" class which caused capability2
    denials (e.g. block_suspend) to be reported as "access" denials.
    
    fixes: https://bugzilla.redhat.com/show_bug.cgi?id=1360392
    
    type=AVC msg=audit(1468324670.938:596175): avc:  denied
    { block_suspend } for  pid=8442 comm="smtp" capability=36
    scontext=system_u:system_r:postfix_smtp_t:s0
    tcontext=system_u:system_r:postfix_smtp_t:s0 tclass=capability2
    
    SELinux is preventing smtp from block_suspend access on the capability2 Unknown.
    
    Signed-off-by: Vit Mojzis <vmojzis@redhat.com>