Change message for VIR_FROM_RPC error domain

The VIR_FROM_RPC error domain is used generically for any RPC
problem, not simply XML-RPC problems.

* src/util/virterror.c: s/XML-RPC/RPC/

src/util/virterror.c

@@ -105,7 +105,7 @@ static const char *virErrorDomainName(virErrorDomain domain) {
             dom = "Domain ";
             break;
         case VIR_FROM_RPC:
-            dom = "XML-RPC ";
+            dom = "RPC ";
             break;
         case VIR_FROM_QEMU:
             dom = "QEMU ";