Issue-ID: VNFRQTS-886 optimization in git clone using --depth

Issue-ID: VNFRQTS-886 optimization in git clone using --depth

optimize the git clone using --depth flag in term of size of clone
and also in term's of time taken to fetch the files and commit history
of whole repository .

Respective issue with Issue-ID: VNFRQTS-886 is created at

https://jira.onap.org/browse/VNFRQTS-886

More detail can be found at blog
https://www.atlassian.com/git/tutorials/big-repositories

Signed-off-by: Pratik Raj <rajpratik71@gmail.com>
Change-Id: I34b4820b36ed31a6f86f0b09cb8a5bad8ca1e402