xci: Use master branch of devops

xci: Use master branch of devops

Till now we usually clone the osm-devops repo of v4.0.1 and
run the OSM installer file from it. v4.0.1 isn't stable anymore.
OSM (upstream) has moved to release branch model (v4.0 is the
stable one now). Since the integration will be completed with
another patch, we can move to the master branch.

https://gerrit.opnfv.org/gerrit/#/c/63129/

installer-type:osa
deploy-scenario:os-nosdn-osm

Change-Id: I40a7ae3762774bb615638d575814ab13845ac844
Signed-off-by: Venkata Harshavardhan Reddy Allu <venkataharshavardhan_ven@srmuniv.edu.in>