core:  Host life cycle broken for jsonrpc

Networking issue was translated to VDSErrorException whereas it should
be translated to VDSNetworkException


Bug-Url: https://bugzilla.redhat.com/1127685
Signed-off-by: pkliczewski <piotr.kliczewski@gmail.com>
Change-Id: I9f6921510c9f42f55c5cc9ec8d8a6daff215c52d
(cherry picked from commit 6c261dc6188f8d345567393c8d475488abf78e3f)