Host internal management network: use "execute_command_get_output" rather than lower-level "safe_close_and_exec"
Host internal management network: use "execute_command_get_output" rather than lower-level "safe_close_and_exec"

Note the run() function can now throw exceptions, however the only caller already has a try/with.

Signed-off-by: David Scott <63c9eb0ea83039690fefa11afe17873ba8278a56@eu.citrix.com>

djs55/xcp-rrdd,koushikcgit/xcp-rrdd,djs55/xcp-networkd,robhoes/squeezed,koushikcgit/xcp-rrdd,simonjbeaumont/xcp-rrdd,simonjbeaumont/xcp-rrdd,sharady/xcp-networkd,djs55/xcp-rrdd,sharady/xcp-networkd,djs55/squeezed,djs55/xcp-networkd,johnelse/xcp-rrdd,koushikcgit/xcp-networkd,koushikcgit/xcp-networkd,koushikcgit/xcp-rrdd,johnelse/xcp-rrdd