use esd_close instead of close when disconnecting from the esd server

for setting rate in OSS plugin, bump sample rate tolerance from 1% to 2% 
(nForce2 uses a sample rate of 48813)


git-svn-id: http://svn.xiph.org/trunk/ao@6751 0101bb08-14d6-0310-b084-bc0e0c8e3800