Update INSTALL.md

INSTALL.md

@@ -206,7 +206,7 @@ calling a BLAS function. A simple way to check this
 
 ```python
 python -c "import faiss, numpy
-faiss.Kmeans(10, 20).train(numpy.random.rand(1000, 10).astype('float32'))"
+faiss.Kmeans(10, 20).train(numpy.random.rand(1000, 10).astype('float32'))
 ```