Address Issue 181 : Failing to set current on A4A boards

Umikaze 2.2.1-RC2 includes updated versions of Adafruit-BBIO
This new library changes how the SPI module works.

This changes the DAC class to match the updated SPI module
to use /dev/spidev2_0

redeem/DAC.py

@@ -58,10 +58,7 @@ def __init__(self, channel):
     self.offset = 0.0
     if 'SPI' in globals():
       # init the SPI for the DAC
-      try:
-        self.spi2_0 = SPI(0, 0)
-      except IOError:
-        self.spi2_0 = SPI(1, 0)
+      self.spi2_0 = SPI(2, 0)
       self.spi2_0.bpw = 8
       self.spi2_0.mode = 1
     else: