rename {git,ssh}-jenkin-mwext-sync.sh

Obviously GIT_SSH should point to ssh command, not the git one!

Change-Id: Iaa44ecd57defa5dd8c6e4dc16b04a42f357f953d
make ssh-jenkins-mwext-sync verbose and strict (-x -e)

Change-Id: Icc73ff856a9c622ceadffef93f00c5db7ef2c2ef