[JENKINS][FIXED] changing /tmp to mount on / and not tmpfs

[Eyal Edri]

fyi,

recently few gwt jobs have been failing on out of space issue on some jenkins slaves on jenkins.ovirt.org.
after looking into it, it seems some f19 slaves have /tmp mounted on tmpfs.
it seems the 3GB assigned to it were not enough, and according to [1] that mount can be disabled.

so i've made the change for jenkins-f19-slave02, and if anyone encounters this on another slave,
you know what do to now. 

I haven't puppetized it since its requires a reboot.

[1] https://fedoraproject.org/wiki/Features/tmp-on-tmpfs#Release_Notes (thanks ewoud for pointing me to it)
    the command needed: "systemctl mask tmp.mount", and reboot

Eyal.