removed php5.4 from travis build.
removed php5.4 from travis build.

its EOL.
nibsirahsieu/Propel2,cristianoc72/Propel2,SwissalpS/Propel2,ikeyan/Propel2,peter17/Propel2,nibsirahsieu/Propel2,marcj/Propel2,marcj/Propel2,propelorm/Propel2,jeremydenoun/Propel2,ikeyan/Propel2,jeremydenoun/Propel2,peter17/Propel2,propelorm/Propel2,mhitza/Propel2,cristianoc72/Propel2,mhitza/Propel2,SwissalpS/Propel2