ExtraSettings.php sets tmpfs to Jenkins user homedir

The hardcoded /var/lib/jenkins does not work whenever the job is being
triggered on a slave which uses 'jenkins-slave' as a username and has
the tmpfs mounted at /var/lib/jenkins-slave/tmpfs .

ant script need to be updated as well.

Change-Id: I0f48feb4cf7106ac53a8ae628e421cb81d5c67d7
ant: points sqlite.dir.tempfs to $HOME/tmpfs

The jenkins-slave have tmps under their homedir just like jenkins user.
Get rid of the hardcoded '/var/lib/jenkins' home dir.

Change-Id: I177a2307249f589c7aa9acf901baa8dfca77a64b