https://bugzilla.redhat.com/show_bug.cgi?id=1186969

When generating the path to the dir for a CIFS/Samba driver, the code
would generate a source path for the mount using "%s:%s" while the
mount.cifs expects to see "//%s/%s". So check for the cifsfs and
format the source path appropriately.

Additionally, since there is no means to authenticate, the mount
needs a "-o guest" on the command line in order to anonymously mount
the Samba directory.