Probe: Don't report dead or defunct processes

[bboreham]

If the state is reported as dead or zombie, return an error so the process will be skipped.

This will fix the direct cause of the situation described at #3330

[satyamz]

I tried this with sample zombie process. It worked!

$ ./zombie & 
[1] 4148
$ parent process - 4148
child process - 4149
$ ps axl  | grep Z
F   UID   PID  PPID PRI  NI    VSZ   RSS WCHAN  STAT TTY        TIME COMMAND
1  1001  4149  4148  20   0      0     0 -      Z    pts/0      0:00 [zombie] <defunct>
4  1001  4321 30988  20   0   9120   448 -      S+   pts/0      0:00 grep Z

Process was not in the Unconnected nodes too.