Fix makefile. Symbolic link update was wrong.

singularity/Makefile

@@ -4,8 +4,9 @@ ifeq ($(PREFIX),)
 	PREFIX := /opt/bioinfo_utils
 endif
 
+all: run_pipeline
 
-install: all
+install: run_pipeline
 	install -d $(PREFIX)_$(VERSION)/bin
 	install run_pipeline $(PREFIX)_$(VERSION)/bin/.
 	install run_pipeline.sh $(PREFIX)_$(VERSION)/bin/.
@@ -13,9 +14,7 @@ install: all
 	do \
 	    ln -sf $(PREFIX)_$(VERSION)/bin/run_pipeline.sh $(PREFIX)_$(VERSION)/bin/run_$${datatype}_pipeline; \
 	done
-	ln -sf $(PREFIX)_$(VERSION) $(PREFIX)
-
-all: run_pipeline
+	ln -sfn $(PREFIX)_$(VERSION) $(PREFIX)
 
 # Should depend on the rest of the repository.
 run_pipeline: run_pipeline.def