qemu: store the emulator name in the capabilities XML

We don't need this for any functional purpose, but when debugging hosts
it is useful to know what binary a given capabilities XML document is
associated with.

Reviewed-by: Michal Privoznik <mprivozn@redhat.com>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>

tests/testutilsqemu.c

@@ -283,11 +283,14 @@ qemuTestParseCapabilitiesArch(virArch arch,
                               const char *capsFile)
 {
     virQEMUCapsPtr qemuCaps = NULL;
+    char *binary = g_strdup_printf("/usr/bin/qemu-system-%s",
+                                   virArchToString(arch));
 
-    if (!(qemuCaps = virQEMUCapsNew()) ||
+    if (!(qemuCaps = virQEMUCapsNewBinary(binary)) ||
         virQEMUCapsLoadCache(arch, qemuCaps, capsFile) < 0)
         goto error;
 
+    virQEMUCapsSetInvalidation(qemuCaps, false);
     return qemuCaps;
 
  error: