Replace daemon-conf test script with a proper test case

Replace daemon-conf test script with a proper test case

The daemon-conf test script continues to be very fragile to
changes in libvirt. It currently fails 1 time in 3/4 due
to race conditions in startup/shutdown of the test script.

Replace it with a proper test case tailored to the code
being tested

* tests/Makefile.am: Remove daemon-conf, add libvirtdconftest
* tests/daemon-conf: Delete obsolete test
* tests/libvirtdconftest.c: Test config file handling