prototypes: xci: xci-deploy.sh: Append trailing slash for rsync vars

prototypes: xci: xci-deploy.sh: Append trailing slash for rsync vars

The 'synchronize' Ansible module uses rsync and for that we need
to indicate that we want to copy the contents of the development path
and not the development path itself. As such we need to ensure that a
trailing slash is always appended to the user variables but we need to
also ensure that we will not end up with double slashes.

Change-Id: I0103b754585931fa1dcd3966c52d7e4a8f2f63f6
Signed-off-by: Markos Chandras <mchandras@suse.de>