main: use process loop

In reference [1], sdbusplus introduces its own process loop. This patch
uses the sdbusplus built-in process loop instead of writing our own
loop.

[1] https://gerrit.openbmc.org/c/openbmc/sdbusplus/+/56891

Tested: the local user manager daemon is working correct on QEMU.

Signed-off-by: Nan Zhou <nanzhoumails@gmail.com>
Change-Id: I7fc51b463a0c02be707f5778ceba40087af8e131
1 file changed