Incorrect GPIO values of MISO and MOSI in sensors/mcp3008.py

[astrapotro]

Values of self.SPIMISO and self.SPIMOSI in sensors/mcp3008.py are wrongly coded.
This is how it is:
self.SPIMOSI = 23
self.SPIMISO = 24
And this is how i've done to work well in my raspi v1 b:
self.SPIMOSI = 24
self.SPIMISO = 23