Re-enable special case for silence mode.
Re-enable special case for silence mode.

Even if nobody supports this yet in IAX2, this still helps at the beginning of calls, where there is a
delay between accepting the call and receiving voice.

example: guest@iax2.fwdnet.net/613


git-svn-id: 9ed0004971709408f906b8bdafa7f98a7bcab630@344 f854266a-e20d-0410-a9be-8852184c940f

zlargon/iaxclient,zlargon/iaxclient,zlargon/iaxclient,zlargon/iaxclient,zlargon/iaxclient