[travis] Do some steps in install step

.travis.yml

@@ -5,10 +5,12 @@ compiler:
 
 cache: apt
 
-before_script:
+before_install:
   - sudo apt-get update -qq
   - sudo add-apt-repository ppa:ubuntugis/ppa -y
   - sudo apt-get install bison cmake doxygen flex git graphviz grass-dev libexpat1-dev libfcgi-dev libgdal1-dev libgeos-dev libgsl0-dev libopenscenegraph-dev libosgearth-dev libpq-dev libproj-dev libqscintilla2-dev libqt4-dev libqt4-opengl-dev libqtwebkit-dev libqwt-dev libspatialindex-dev libspatialite-dev libsqlite3-dev lighttpd pkg-config poppler-utils pyqt4-dev-tools python python-dev python-qt4 python-qt4-dev python-sip python-sip-dev spawn-fcgi txt2tags xauth xfonts-100dpi xfonts-75dpi xfonts-base xfonts-scalable xvfb
+
+install:
   - mkdir build
   - cd build
   - cmake -DWITH_MAPSERVER=ON -DWITH_STAGED_PLUGINS=OFF -DWITH_GRASS=OFF -DSUPPRESS_QT_WARNINGS=ON ..