Infra: Install MADlib on non-default schema in Jenkins
Infra: Install MADlib on non-default schema in Jenkins

Install MADlib on schema `mad` instead of default schema
`madlib` for the Jenkins PR and Master CI builds.
This would help us identify issues that correspond to
hard-coding `madlib` in the code/tests.

Closes #207

njayaram2/incubator-madlib,madlib/madlib,iyerr3/incubator-madlib,orhankislal/incubator-madlib,njayaram2/incubator-madlib,njayaram2/madlib,madlib/madlib,madlib/madlib,orhankislal/incubator-madlib,orhankislal/madlib,njayaram2/incubator-madlib,iyerr3/incubator-madlib,iyerr3/incubator-madlib,orhankislal/incubator-madlib,orhankislal/incubator-madlib,njayaram2/madlib,njayaram2/madlib,apache/incubator-madlib,njayaram2/madlib,hpandeycodeit/incubator-madlib,orhankislal/madlib,apache/incubator-madlib,orhankislal/madlib,njayaram2/madlib,orhankislal/madlib,hpandeycodeit/incubator-madlib,hpandeycodeit/incubator-madlib,orhankislal/madlib,apache/incubator-madlib,iyerr3/incubator-madlib,apache/incubator-madlib,madlib/madlib,njayaram2/incubator-madlib,apache/incubator-madlib,orhankislal/incubator-madlib,hpandeycodeit/incubator-madlib,hpandeycodeit/incubator-madlib,madlib/madlib,njayaram2/incubator-madlib,iyerr3/incubator-madlib