link OpenBLAS as blas

OpenBLAS is most easily configured by `update-alternatives` or other
symlink strategies.

See https://github.com/BVLC/caffe/issues/314#issuecomment-40703048

Makefile

@@ -252,7 +252,7 @@ ifeq ($(BLAS), mkl)
 	BLAS_LIB ?= $(MKL_DIR)/lib $(MKL_DIR)/lib/intel64
 else ifeq ($(BLAS), open)
 	# OpenBLAS
-	LIBRARIES += openblas
+	LIBRARIES += blas
 else
 	# ATLAS
 	ifeq ($(LINUX), 1)