qemu-ga: drop unused local err variable

Commit 125b310e ("qemu-ga: move
channel/transport functionality into wrapper class") stopped using the
local err variable in channel_event_cb().

This patch deletes the unused variable.
Signed-off-by: NStefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: NFam Zheng <famz@redhat.com>
Signed-off-by: NMichael Roth <mdroth@linux.vnet.ibm.com>

qga/main.c

@@ -618,13 +618,7 @@ static gboolean channel_event_cb(GIOCondition condition, gpointer data)
     GAState *s = data;
     gchar buf[QGA_READ_COUNT_DEFAULT+1];
     gsize count;
-    GError *err = NULL;
     GIOStatus status = ga_channel_read(s->channel, buf, QGA_READ_COUNT_DEFAULT, &count);
-    if (err != NULL) {
-        g_warning("error reading channel: %s", err->message);
-        g_error_free(err);
-        return false;
-    }
     switch (status) {
     case G_IO_STATUS_ERROR:
         g_warning("error reading channel");