qemu: Fix name comparison in qemuMonitorJSONBlockIoThrottleInfo()

The string comparison logic was inverted and matched the first drive
that does *not* have the name we search for.
Signed-off-by: NStefan Hajnoczi <stefanha@redhat.com>
(cherry picked from commit 23d47b33)

src/qemu/qemu_monitor_json.c

@@ -3518,7 +3518,7 @@ qemuMonitorJSONBlockIoThrottleInfo(virJSONValuePtr result,
             goto cleanup;
         }
 
-        if (STREQ(current_dev, device))
+        if (STRNEQ(current_dev, device))
             continue;
 
         found = 1;