[build] clear packages only on travis (needed to avoid caching them)

.travis.yml

@@ -23,6 +23,8 @@ before_install:
 
 install:
 - ./setup-libraries.sh
+- rm -rf mapnik-packaging/out/packages
+
 
 before_script:
 - if [ ${CXX} = "g++" ]; then export CXX="g++-4.8" ; fi

setup-libraries.sh

@@ -77,8 +77,6 @@ source MacOSX.sh
     if [ ! -d out/build-cpp11-libcpp-x86_64/include/boost ] ; then ./scripts/build_boost.sh `pwd`/../../src/ `pwd`/../../linux/ `pwd`/../../common/ ; fi
     echo '     ...done'
 
-rm -rf out/packages
-
 ./scripts/make_universal.sh
 
 cd ../../
@@ -96,8 +94,6 @@ source Linux.sh
     if [ ! -f out/build-cpp11-libstdcpp-gcc-x86_64/lib/libcurl.a ] ; then ./scripts/build_curl.sh ; fi
     if [ ! -d out/build-cpp11-libstdcpp-gcc-x86_64/include/boost ] ; then ./scripts/build_boost.sh `pwd`/../../src/ `pwd`/../../linux/ `pwd`/../../common/ ; fi
 
-rm -rf out/packages
-
 cd ../../
 ./configure \
 --pkg-config-root=`pwd`/mapnik-packaging/osx/out/build-cpp11-libstdcpp-gcc-x86_64/lib/pkgconfig \