XOP-261: Make sure that stunnel listens on the right addresses

This may be "all IP addresses" or only localhost, and IPv4 or IPv6.

Signed-off-by: Rob Hoes <rob.hoes@citrix.com>
CA-99541: Fix himn when a VM cannot connect to Xapi.

Signed-off-by: Jerome Maloberti <jerome.maloberti@citrix.com>
XOP-261: Simplify management interface management

Signed-off-by: Rob Hoes <rob.hoes@citrix.com>
XOP-261: Remove some unused stuff in Xapi_mgmt_iface

Signed-off-by: Rob Hoes <rob.hoes@citrix.com>
XOP-261: Only restart stunnel when actually changing which IP xapi is listening on

Signed-off-by: Rob Hoes <rob.hoes@citrix.com>