[travis] Fix warnings about invalid ccache options

https://travis-ci.org/qgis/QGIS/jobs/127438282#L731

Author: m-kuhn

ci/travis/linux/qt5/script.sh

@@ -3,8 +3,8 @@ export CTEST_PARALLEL_LEVEL=1
 
 DIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd )"
 
-ccache -o max_size=150M
-ccache -o run_second_cpp=true
+# ccache -o max_size=150M
+# ccache -o run_second_cpp=true
 
 xvfb-run ctest -V -E "$(cat ${DIR}/blacklist.txt | paste -sd '|' -)" -S ./qgis-test-travis.ctest --output-on-failure
 # xvfb-run ctest -V -S ./qgis-test-travis.ctest --output-on-failure