Log client errors in libvirtd at debug priority

This reverts commit

 Log all errors at level INFO to stop polluting syslog
 04bd0360f3.

and makes virRaiseErrorFull() log errors at debug priority
when called from inside libvirtd. This stops libvirtd from
polluting it's own log with client errors at error priority
that'll be reported and logged on the client side anyway.

daemon/libvirtd.c

@@ -3083,6 +3083,10 @@ int main(int argc, char **argv) {
         exit(EXIT_FAILURE);
     }
 
+    /* Set error logging priority to debug, so client errors don't
+     * show up as errors in the daemon log */
+    virErrorSetLogPriority(VIR_LOG_DEBUG);
+
     while (1) {
         int optidx = 0;
         int c;