bitbake: bitbake: xmlrpc: set single use mode differently

bitbake: bitbake: xmlrpc: set single use mode differently

Currently xmlrpc server implicitly sets itself into single use mode
when bitbake server is started with anonymous port (0) or no port is
provided in command line. In this mode bitbake shuts down xmlrpc server
after build is done. This assumption is incorrect in some cases.
For example Toaster uses bitbake in this mode and expects xmlrpc server
to stay in memory.

Till recent changes single use mode was always unset due to the bug.
When the bug was fixed it broke toaster builds as Toaster couldn't
communicate with bitbake server in single use mode.

Reimplemented logic of setting single use mode. The mode is explicity
set when --server-only command line parameter is not provided to bitbake.
It doesn't depend on the port number anymore.

[YOCTO #9275]
[YOCTO #9240]
[YOCTO #9252]

(Bitbake rev: afc0dd5c532684f6201b1e12bbf4c226ea19062d)

Signed-off-by: Ed Bartosh <ed.bartosh@linux.intel.com>
Signed-off-by: Elliot Smith <elliot.smith@intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>