openbsd: fix virtualenv bootstrap

bootstrap-openbsd.sh

@@ -24,10 +24,13 @@ then
 	git clone https://git.ik.bme.hu/circle/agent.git agent
 fi
 
-python2 -m virtualenv /usr/local/virtualenvs/agent
-. /usr/local/virtualenv/agent/bin/activate
-pip install -r /root/requirements.txt
-deactivate
+virtenv=/usr/local/virtualenvs/agent
+if [ ! -d $virtenv ]; then
+	python2 -m virtualenv $virtenv
+	. $virtenv/bin/activate
+	pip install -r /root/agent/requirements.txt
+	deactivate
+fi
 
 cp bootstrap/openbsd/usr/sbin/mount_circle-userstore /usr/sbin/mount_circle-userstore
 cp bootstrap/openbsd/rc.d/agent /etc/rc.d/agent