The rear brakes only provide about 10% of the braking force or something and I am 100% sure you should have been able to avoid this using only the front brakes.
+1
What happened to you was really nothing. I had a buddy in San Francisco who forgot to hook his front brake cable hanger back on after changing his front tube. He lives at the top of a hill and fortunately he didn't make it all the way down to the intersection before he realized he had no stopping power on the front wheel. A sharp turn and some sliding managed to stop him without any harm, but he was glad he didn't bomb down the hill before applying the brakes.