Fix build with polkit0

I missed adding libvirt_driver_remote.la to libvirtd_LDADD in
commit b8adfcc6, which didn't cause a problem in 0.9.6 but
results in this build error in 0.9.7

libvirtd-remote.o: In function `remoteDispatchAuthPolkit':
remote.c:(.text+0x188dd): undefined reference to `virNetServerGetDBusConn'

daemon/Makefile.am

@@ -156,6 +156,10 @@ endif
 if WITH_NWFILTER
     libvirtd_LDADD += ../src/libvirt_driver_nwfilter.la
 endif
+
+if HAVE_POLKIT0
+    libvirtd_LDADD += ../src/libvirt_driver_remote.la
+endif
 endif
 
 libvirtd_LDADD += ../src/libvirt.la