framework: Handle sockets with abstract path properly
    
    Abstract socket paths start with \0, which caused os.stat() to crash
    Replace the \0 symbol(s) with @ to denote this is not a filesystem path.
    
    Fixes:
      # cat avc
    
      type=AVC msg=audit(1574094303.139:1096): avc:  denied  { sendto } for  pid=18278 comm="dcbtool" path=002F636F6D2F696E74656C2F6C6C64706164 scontext=sysadm_u:sysadm_r:sysadm_t:s0-s0:c0.c1023 tcontext=system_u:system_r:lldpad_t:s0 tclass=unix_dgram_socket permissive=0
      #sealert -a avc
      100% done
      embedded null byte
      100% done
      found 0 alerts in avc
    
      AVC analysis is not generated!