[zebra 18626] move zebra socket paths to configure.ac

[zebra 18626] move zebra socket paths to configure.ac

moved definition of the various socket paths from the
per daemon header files into configure.ac. it will set the paths to
be in the directory specified by --localstatedir=<prefix> or
otherwise will try to guess as best it can ( a la pid file path
detection - which probably should try reference ${prefix} too).

the present hardcoded socket path, /tmp, isnt really correct. should
be in /var somewhere really.