The massive credit expansion is exactly what you don't want if you want to ease the housing market.
The Economist got almost everything in this story wrong.
I have personal experience of being to Nigeria a few times on infrastructure subcontract projects.
The predominant portion of those abandoned construction sites are made by plain fraudsters, take money, make a semblance of construction going, then vanish with money.
Urban apartment housing in most of Africa is seen as something for a more affluent, and well off, much alike how it is in Asia, and not the other way around as it is in the West.
There are quite proficient builders in economically relatively well doing African countries. Take a look on http://www.mhfproperties.com/
Where fraud proliferates are 2nd tier African economies, and housing for people lower on the class ladder (ones who are just entering the middle class, and still want save hard on housing.)
The shortages of cement, steel, and construction supplies bear much more on the availability of housing than any of that "liquidity" thing.
Africa needs more factories, more mills, more kilns, more technical know how. At the moment even such basic things like petrol, and cement are largely import only even in most developed African economies.
This leads to those countries squandering their short FX resources gained largely from agricultural exports, which could've been spent in import of something more useful, and productive, like plant machinery.