Bug#539681: No more crashes with 1.6.1.0~dfsg-1.0.0jones1

[Eloy Paris]

Just downgraded and tested 1.6.1.0~dfsg-1.0.0jones1 -- I no longer see
the crashes that I was experiencing with 1.6.2beta3.

I was able to reliably reproduce this crash by:

- Calling my number from the outside
- Logging into the voice mail system
- Selecting 3 (advanced options) and 4 (transfer call)
- Dialing an outside number

In other words, coming in via SIP and then going out via the same SIP
channel.

Following the above procedure with 1.6.1.0~dfsg-1.0.0jones1 no longer
yields a crash.