Fix 'UserDown' QA
Fix 'UserDown' QA

Increase instance shutdown timeout and make call 'pkill' more
reliable, which should fix the KVM QA.

Signed-off-by: Jose A. Lopes <0fb9c4f8511df4ec2ae28af879e9d462f6218a2c@google.com>
Reviewed-by: Michele Tartara <05f7077a2c6cbbdc4af4ba42e3ef89a0df846179@google.com>

ganeti/ganeti,andir/ganeti,ganeti-github-testing/ganeti-test-1,onponomarev/ganeti,grnet/snf-ganeti,andir/ganeti,mbakke/ganeti,ganeti-github-testing/ganeti-test-1,ganeti/ganeti,mbakke/ganeti,grnet/snf-ganeti,mbakke/ganeti,leshchevds/ganeti,yiannist/ganeti,leshchevds/ganeti,bitemyapp/ganeti,apyrgio/ganeti,onponomarev/ganeti,dimara/ganeti,ganeti/ganeti,yiannist/ganeti,dimara/ganeti,yiannist/ganeti,apyrgio/ganeti,andir/ganeti,leshchevds/ganeti,bitemyapp/ganeti