CA-172563: unix: make the client connection thread tail-recursive
CA-172563: unix: make the client connection thread tail-recursive

We were making non-tailrec calls in the middle of a match, where the
match case handling was irrelevant anyway. Fix by making the recursive
call right at the end of the function.

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

djs55/message-switch,djs55/message-switch-1,djs55/message-switch,djs55/message-switch-1,xapi-project/message-switch,xapi-project/message-switch,xapi-project/message-switch,djs55/message-switch-1,djs55/message-switch