core: Improve error / debug messages for hotplug pipe handling

Signed-off-by: Hans de Goede <hdegoede@redhat.com>

libusb/io.c

diff --git a/libusb/io.c b/libusb/io.c
index d295cec..595c92e 100644
--- a/libusb/io.c
+++ b/libusb/io.c
@@ -1943,9 +1943,13 @@
 		libusb_hotplug_message message;
 		ssize_t ret;
 
+		usbi_dbg("caught a fish on the hotplug pipe");
+
 		/* read the message from the hotplug thread */
 		ret = usbi_read(ctx->hotplug_pipe[0], &message, sizeof (message));
 		if (ret < sizeof(message)) {
+			usbi_err(ctx, "hotplug pipe read error %d < %d",
+				 ret, sizeof(message));
 			ret = LIBUSB_ERROR_OTHER;
 			goto handled;
 		}

libusb/version_nano.h

diff --git a/libusb/version_nano.h b/libusb/version_nano.h
index 3db6b73..b586028 100644
--- a/libusb/version_nano.h
+++ b/libusb/version_nano.h
@@ -1 +1 @@
-#define LIBUSB_NANO 10689
+#define LIBUSB_NANO 10690