Fixes a leak when parsing parameters with quotes such as TZID="BLAHBLAHBLAH"
The normal path is for parameters to be unquoted, so no string copy is made and a pointer to the middle of an existing buffer is returned. However, quoted strings make a copy and return a new buffer. I changed the unquoted path to also return a new buffer, then ensured that the buffer is released.
I also removed the buf_value paramter from the function since nothing was using it.