Fix installation step on Windows (regression from e8306f623a)

Since the DLL now has a fixed name there is no need to install a versioned alias too.

Makefile.install

@@ -71,11 +71,9 @@ ifeq ($(OSNAME), Darwin)
 endif
 ifeq ($(OSNAME), WINNT)
 	-cp $(LIBDLLNAME) $(OPENBLAS_LIBRARY_DIR)
-	-ln -fs $(OPENBLAS_LIBRARY_DIR)/$(LIBDLLNAME) $(OPENBLAS_LIBRARY_DIR)/$(LIBPREFIX).dll
 endif
 ifeq ($(OSNAME), CYGWIN_NT)
 	-cp $(LIBDLLNAME) $(OPENBLAS_LIBRARY_DIR)
-	-ln -fs $(OPENBLAS_LIBRARY_DIR)/$(LIBDLLNAME) $(OPENBLAS_LIBRARY_DIR)/$(LIBPREFIX).dll
 endif
 
 	@echo Install OK!