follow up fix related to 933b05c331 (ticket #263 uninitialized dir variable): fix...

follow up fix related to 933b05c331 (ticket #263 uninitialized dir variable): fix the three other places where dir parameter wasn't set prior to entry to a snd_pcm_*_get_* function. There is some ambiguity about (a) whether this is intentional (i.e. use the rounding dir returned by previous *_get_* call, the PA source code does not indicate), and (b) whether it is meaningful (i.e. whether *_get_* functions actually use the value upon input -- the ALSA docs are not clear. regarding (a): I don't think it's intentional, i think it was just oversight. In any case thr risk is low: the underlying values of period_size, periods_max, periods_min, are all integer and should not be rounded, get_rate_min/get_rate_max are used only for debug reporting (I've set them to 0,0 for a minimal change from the current code, but -1,1 makes more sense).