When using rstpctl command to stop the rstp service, the daemon will
stop unexpectedly.
it exits because the rcvmsg returns error that no buffer space available, 
but this is not a critical issue, let it ignore this and continue.

Change-Id: Ia20978a9dd846c24a6fef9604346f1356f44adc3
Signed-off-by: Ken Zhu <guigenz@codeaurora.org>