Add back quartz target on travis.

[TotoGaz]

Resolution of https://github.com/GEOSX/GEOSX/issues/1889 emphasized that the quartz target on travis was outdated (in a nutshell, old version of clang and more important, old gcc headers). See full discussion here https://github.com/GEOSX/thirdPartyLibs/pull/200.

The target was removed, but a new target should replace the old one!