fix install tests

.ci/travis-test.sh

@@ -53,10 +53,13 @@ if [ "$A" == "32" ] ; then
     XFLAGS_="$XFLAGS_ -m32"
 fi
 
+install=`pwd`/install
+mkdir install
 mkdir build
 cd build
 cmake -DCMAKE_C_COMPILER=$CC_ -DCMAKE_C_FLAGS="$CFLAGS_" \
       -DCMAKE_CXX_COMPILER=$CXX_ -DCMAKE_CXX_FLAGS="$XFLAGS_" \
+      -DCMAKE_INSTALL_PREFIX="$install" \
       -DCMAKE_BUILD_TYPE=$BT \
       -DRYML_DEV=ON \
       -DRYML_BUILD_BENCHMARKS=OFF \