Description of problem:

case: connectStoragePool doesn't return on host & and host recovery fails
cause: several vdsm sudo sub-procosses left in defunct state which stuck other threads work


root      8102  0.0  0.0  51048  1904 ?        S<   16:00   0:00 /usr/bin/sudo -n /usr/bin/python /usr/share/vdsm/supervdsmServer.pyc 3e57466d-f015-4686-bea5-d91b291b1296 8063
root     28573  0.0  0.0      0     0 ?        Z<   17:03   0:00 [sudo] <defunct>
root     29226  0.0  0.0      0     0 ?        Z<   17:04   0:00 [sudo] <defunct>
root     29675  0.0  0.0      0     0 ?        Z<   17:04   0:00 [sudo] <defunct>
root     29796  0.0  0.0      0     0 ?        Z<   17:04   0:00 [sudo] <defunct>
root     31861  0.0  0.0      0     0 ?        Z<   17:04   0:00 [sudo] <defunct>
root     32113  0.0  0.0      0     0 ?        Z<   17:04   0:00 [sudo] <defunct>

reproducer: not easy
repro steps:

1) VMs are running 
2) logout from iscsi-session 
3) restart VDSM

see attached logs

not sure if its a regression.