Generate new ca_email for ssl cert issuer for each software instance.

This is okay for kvm case, where only one cert is requested only once.

slapos/recipe/kvm/__init__.py

@@ -54,7 +54,9 @@ class Recipe(BaseSlapRecipe):
     self.requirements, self.ws           = self.egg.working_set()
     self.cron_d                          = self.installCrond()
 
-    self.ca_conf                         = self.installCertificateAuthority()
+    ca_email = binascii.hexlify(os.urandom(10))
+    self.ca_conf                         = self.installCertificateAuthority(
+                                               ca_email = ca_email)
     self.key_path, self.certificate_path = self.requestCertificate('noVNC')
 
     # Install the socket_connection_attempt script