building-gdp: Adjust after migration to single branch

[gmacario]

As of 2016-06-18, reproducing building-gdp.md produces the following error:

Started by user anonymous
[EnvInject] - Loading node environment variables.
Building in workspace /var/jenkins_home/jobs/GENIVI/jobs/build_gdp/workspace
Cloning the remote Git repository
Cloning repository https://github.com/GENIVI/genivi-dev-platform.git
 > git init /var/jenkins_home/jobs/GENIVI/jobs/build_gdp/workspace # timeout=10
Fetching upstream changes from https://github.com/GENIVI/genivi-dev-platform.git
 > git --version # timeout=10
 > git -c core.askpass=true fetch --tags --progress https://github.com/GENIVI/genivi-dev-platform.git +refs/heads/*:refs/remotes/origin/*
 > git config remote.origin.url https://github.com/GENIVI/genivi-dev-platform.git # timeout=10
 > git config --add remote.origin.fetch +refs/heads/*:refs/remotes/origin/* # timeout=10
 > git config remote.origin.url https://github.com/GENIVI/genivi-dev-platform.git # timeout=10
Fetching upstream changes from https://github.com/GENIVI/genivi-dev-platform.git
 > git -c core.askpass=true fetch --tags --progress https://github.com/GENIVI/genivi-dev-platform.git +refs/heads/*:refs/remotes/origin/*
 > git rev-parse refs/remotes/origin/qemux86-64^{commit} # timeout=10
 > git rev-parse refs/remotes/origin/origin/qemux86-64^{commit} # timeout=10
 > git rev-parse origin/qemux86-64^{commit} # timeout=10
ERROR: Couldn't find any revision to build. Verify the repository and branch configuration for this job.
Archiving artifacts
Notifying upstream projects of job completion
Finished: FAILURE

This is due to the migration of genivi-dev-platform to the single branch - See TODO

[gmacario]

Trying replacing "Branch specifier" with */master

[gmacario]

Testing instructions at https://github.com/gmacario/easy-jenkins/blob/fix-issue-122/docs/building-gdp.md

[gmacario]

Fix with PR https://github.com/gmacario/easy-jenkins/pull/123