Added cleanup for pygraphviz target.

Author: oubiwann

Makefile

@@ -5,12 +5,13 @@ virtual-env:
 	$(PYTHON) -m venv $(VENV)
 
 pygraphviz:
-	git clone https://github.com/pygraphviz/pygraphviz
-	. $(VENV)/bin/activate && \
+	@git clone https://github.com/pygraphviz/pygraphviz
+	@. $(VENV)/bin/activate && \
 	cd pygraphviz && \
 	git checkout 6c0876c9bb158452f1193d562531d258e9193f2e && \
 	git apply ../patches/graphviz-includes.diff && \
 	python setup.py install
+	@rm -rf pygraphviz
 
 
 deps: pygraphviz