Poll() event handling introduced in 7.4 may leave a zombie

[olofhagsand]

In 7.4 the event handling was changed from select to poll to allow for more than 1024 file descriptors.
However, killing the restconf daemon may in some cases leave the restconf daemon in a zombie state.
The reason is that the backend does not properly wait for a SIGCHLD.

Workaround: (re)start the restconf daemon.

[olofhagsand]

The following commit added the ability to switch between select() and poll().
d2fc3ce
Select() is default until the poll problem is fixed.