I'm not 100% sure as I haven't tried, but I think the problem you're seeing may be related to the fact I2C is muxed on Galileo, as some other IOs are.
Looking at the IO mapping document: Intel® Galileo IO Mapping I see that the I2C is muxed with ADC (very last line in the table) and by default it's switched to ADC.
So I think you need to do something similar to what SpiderKenny just described in his [very nice! :-)] blog post about using UART pins 0 and 1 to work with 1-wire devices: Using Galileo to read 1-Wire (such as iButton) devices.. Take a look at the source code he provides, there's a function for setting up the muxer to have the UART connected to pins.
Looks like you need to do a similar thing, but for just one GPIO #29, which needs to beset it to 0 instead of the default 1 and that will connect Quark's I2C SDA and SCL lines to pins A4 and A5.