efreet: Fix and clean up the way dbusservicedir is set in the build system

efreet: Fix and clean up the way dbusservicedir is set in the build system

The current code was a mix of r78302 (when edbus2 support was made
optional) and r78867 (when edbus2 support was made a required
dependency).

This patch fixes a few bugs:

 o The syntax of the AC_ARG_WITH call was wrong and `dbusservicedir' was
   always set to "", which meant it was always installed into
   ${datadir}/dbus-1/services.

 o The check for the value of $dbusservicedir was wrong at the end of
   configure.ac, since passing "yes" to --with-dbus-services does not
   make sense.

And simplifies some checks and calls now that edbus2 is mandatory.

Patch by Raphael Kubo da Costa

SVN revision: 79464