Bugfix of repeating lines in configuration file

Both the following files contain multiple dbaas_image keys
1.tests/integration/core.test.conf
2.scripts/conf/test_begin.conf

They have been cleaned up in the fix.

Closes-Bug: #1269813

Change-Id: Ie749b4101e31a0c250ff0f68b552e99507f94fdb
Merge "Bugfix of repeating lines in configuration file"