Issue-ID: APPC-1882 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: APPC-1882  is created at

https://jira.onap.org/browse/APPC-1882

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: Ic5e7169b23662f80f98e192355163159f42182b8