error: Replace error_report() & error_free() with error_report_err()

This is a continuation of the work started in commit 565f65d2:
"error: Use error_report_err() where appropriate"
Signed-off-by: Nzhanghailiang <zhang.zhanghailiang@huawei.com>
Reviewed-by: NEric Blake <eblake@redhat.com>
Reviewed-by: NMarkus Armbruster <armbru@redhat.com>
Signed-off-by: NMichael Tokarev <mjt@tls.msk.ru>

hw/arm/virt.c

@@ -771,7 +771,7 @@ static void machvirt_init(MachineState *machine)
         cc->parse_features(CPU(cpuobj), cpuopts, &err);
         g_free(cpuopts);
         if (err) {
-            error_report("%s", error_get_pretty(err));
+            error_report_err(err);
             exit(1);
         }
 

savevm.c

@@ -941,8 +941,7 @@ int qemu_loadvm_state(QEMUFile *f)
     int file_error_after_eof = -1;
 
     if (qemu_savevm_state_blocked(&local_err)) {
-        error_report("%s", error_get_pretty(local_err));
-        error_free(local_err);
+        error_report_err(local_err);
         return -EINVAL;
     }